The four-month ban handed out to Uruguay striker Luis Suarez for his latest bite, this time on Italy's Giorgio Chiellini, has again highlighted the boundaries of what behaviour is acceptable on a football field.BBC Sport - with the help of pundit Steve Claridge, who played for 22 different clubs in a 29-year professional career - examines just how far you can go before you commit the sport's ultimate sin.BrawlingVerdict: 'Not a big deal'The term 'fight' in football should be used loosely. Very rarely do we see a scrap fit for Madison Square Garden on the pitch, though one or two players have certainly shown they pack a tasty right-hook.Steve ClaridgeFrancis Lee and Norman Hunter threw thunderous punches at one another when Derby met Leeds in 1975, and Hristo Stoichkov was initially handed a life-long ban for his role in a ding-dong in the 1985 Bulgarian Cup final.Stoichkov, who later managed Bulgaria, eventually saw his penance reduced to a month but QPR's Joey Barton served a 12-match ban for igniting a melee on the final day of the 2011-12 season at Manchester City.Barton had been sent off and thrust a knee into Sergio Aguero's thigh before leaving the field. Cue chaos."The actual brawl is not what the incident is about," said BBC Radio 5 live pundit Claridge. "It comes after something. It's not a big deal in my view and part and parcel of a physical game."I can remember playing for Weymouth and good old Vinnie Jones was involved in a fight with our goalkeeper and it got very unsavoury but these things happen and once it's done, it's done."ElbowingMauro Tassotti played seven times for Italy and picked up an eight-match ban in his final outing.Pedro MendesPortsmouth's Pedro Mendes suffered a seizure as a result of an elbow from Ben ThatcherThe defender's vicious elbow to the face of Luis Enrique at the 1994 World Cup bloodied the shirt of the Spanish player but he escaped immediate punishment from the referee as Italy won 2-1 to reach the semi-finals.Ex-Manchester City defender Ben Thatcher also escaped without a red card when his elbow to Pedro Mendes in 2006 left the Portsmouth player needing oxygen next to the pitch. Again, football's authorities had the final say, handing Thatcher an eight-match ban."You can see an elbow that's thrown and one that genuinely goes up for a header," said Claridge. "I could tell you which ones are intentional every time."It can do some serious damage - extreme damage. If you did it 20 years ago you'd have reprisals, no doubt about it, you could get the guy back."If you see something like that it brings a reaction, that's part of being a team-mate. I remember the British Lions rugby team and they would shout a '99' call  [on their 1974 tour of South Africa] when they knew if they heard it they had to fight and look after one another."SpittingFootballers spitting is not an uncommon sight. Rarely a minute goes by during a game where you do not see a footballer depositing various levels of phlegm on the pitch.Footballers spitting at each other is less common though. It not only shocks but also disgusts. The image of Netherlands midfielder Frank Rijkaard spitting into Rudi Voller's mullet twice at the 1990 World Cup is one of the most revolting moments in World Cup history. But why do players dislike it so much?"It was and is the unwritten rule in that you don't do it," said Claridge. "Much like you don't go with another player's wife. You don't lower yourself to that level. It's not even a football thing; in general life, you just don't do it."It's not behaviour we ever want to see, but again, compared to physical harm, it's something players can cope with."Pushing the refPaolo Di Canio's shove on referee Paul Alcock during Sheffield Wednesday's meeting with Arsenal in 1998 was a first in England's highest division.The Italian's reaction to one of his four red cards in the UK saw him banned for 11 games and left pundits, players and supporters aghast.Referees at the time said Di Canio's ban was too short, but he returned four months later following a move to West Ham, where he became a fans' favourite."It won't hurt the referee and it's more of an insult to the authorities," said Claridge. "It's a problem lower down the scale - a real curse in grassroots football - but at the top level, you know the punishment and it doesn't happen."It's a tricky balance though because if you don't question the referee and fight your corner you're accused of having no passion, yet if you do, you're a thug. Deep down, you know as a player if you've gone too far."Blatant cheatingA swipe at the ball on the halfway line is one thing, deciding a fixture and leaving a country's World Cup in tatters is quite another.Diego Maradona's 'Hand of God' goal in 1986 needs no explanation: he leapt, punched, ran away and celebrated as England scratched their heads and exited the World Cup.Over two decades later, Luis Suarez caused similar controversy when he clawed a header off Uruguay's goal-line in the last-minute of extra-time in their 2010 World Cup quarter-final with Ghana.He was sent off, but celebrated in the tunnel when Asamoah Gyan missed the resulting penalty before Uruguay won a subsequent shoot-out.Asked if he would handball on the goal-line to win a trophy, Claridge said: "No. I would push the boundaries but I wouldn't cheat."It sticks in the gut. You've been cheated. As much as you'd like to do the guy some damage for cheating you, he has not hurt you in a physical sense. But on an emotional level it's bad. You just hope that person is punished properly."RacismSuarez, of course has 'previous'. In December 2011 he was given an eight-match ban for racially abusing Manchester United defender Patrice Evra . Since then Uefa has proposed a minimum 10-game suspension for any player found guilty.With Fifa pushing so hard to tackle the issue off the pitch and players reacting so strongly to receiving abuse themselves, is it the one thing footballers detest the most?Claridge said: "I think, as bad as it is emotionally, players get abused for years playing football and develop a thick skin and I think players are more concerned about being physically hurt than anything verbal. Most just know it's not something you do."I also think there is a perception that racism in football is purely white on black, it's not. There are so many communities now represented but in truth, I can honestly say I haven't seen a lot of racism in football. There may be closet racism, but not on the pitch."Faking injuryDiving, simulation, over-exaggeration, lying; call it what you want but in a game of such fine margins, gaining even the slightest advantage can make a huge difference.At the 2002 World Cup, Rivaldo feigned injury, falling to the ground holding his face after a ball was kicked at his leg by Turkish player Hakan Unsal, who was subsequently red-carded.The Brazilian forward was fined £5,180 and in recent years there has been a huge drive to eradicate diving, what Fifa vice-president Jim Boyce has previously said is a "cancer within the game".Dr Maria Kavussanu, an expert in morality in sport at Birmingham University, said: "We have measured all of what we call anti-social behaviours in football like pushing and fouling - they are aggressive - and we have found the people who commit them are most likely to be the ones who dive."Interestingly, you can see as soon as Suarez did what he did with Chiellini and Ivanovic, he faked an injury."I would classify the sins which have an extreme impact on others as worse. Diving is maybe not so bad in that context, but so many children watch, especially the best players, and footballers are role models."ButtingFrance legend Zinedine Zidane's head-butt on Italy's Marco Materazzi in the 2006 World Cup final is one of the most iconic images of the tournament. So much so it was immortalised in a bronze statue in Qatar, only to be removed later.The sheer brutality of the act makes it one of the most savage in the game. Last season Newcastle manager Alan Pardew received a seven-match ban for butting Hull player David Meyler , while Portugal defender Pepe has also seen red at this World Cup for the act."If someone butted me, then we'd be fighting; it's a cowardly act. If you want to fight someone, you fight someone," said Claridge. "If you're talking about what Pepe did, that kind of head-to-head, it won't do damage."There's a massive difference between butting someone and putting your head into someone, and players are strong enough to deal with the mental side of someone trying to provoke a reaction by doing the latter."Kung-fu kickingVerdict: 'No doubt it can be reckless'Eric Cantona kick-started an era of dominance at Manchester United, won four Premier League titles and became a club legend, but, any discussion about this complex character invariably includes an infamous kung-fu kick.The Frenchman leapt over the advertising hoardings at Selhurst Park to kick Crystal Palace fan Matthew Simmons - a man he calls a "hooligan". Cantona said his outburst was for fans who would have liked to do it themselves, but concedes "it was a mistake".Fast forward 15 years and Netherland's midfielder Nigel de Jong brought the martial arts move onto the field, with his brutal blow to the chest of Spain's Xabi Alonso in the 2010 World Cup final.De Jong was only yellow-carded. Cantona was banned for eight months."If the ball is there to be won and you go through someone, if you're honestly going for the ball, you have to do it," Claridge said. "Subconsciously you know if a player has tried to catch you high-up. The lines are blurred as it all comes down to that - was the player being honest? There's no doubt a challenge like that can be reckless."BitingIt sounds almost unthinkable that in the fast-moving environment of a top level football match, a player has time to take a bite out of an opponent.Liverpool's Luis Suarez did just that when he tussled with Chelsea's Branislav Ivanovic in 2013, less than three years after the striker bit the shoulder of PSV Eindhoven's Otman Bakkal.Italy's Giorgio Chiellini became the target of Suarez's latest bite on Tuesday, prompting global reaction and a four-month ban for the Uruguayan."It is not about the act itself, it is the symbol it represents," said Orin Starn, Professor of Cultural Anthropology and History at Duke University in Durham, USA. "It has broken the boundary of the body, which in western culture is a taboo. If you go a long way back it is associated with death and evil."We regard the body as an entity in itself and something that should not be violated. A bad tackle may break someone's leg but there is no violation of the body so we find that more acceptable than being bitten."Queens Park Rangers midfielder Joey Barton disagrees and like Claridge, is more fearful of serious physical harm on the pitch. "All things considered I'd rather receive a bite than a leg-breaking challenge," tweeted Joey Barton  after Suarez's grapple with Chiellini."Whilst he should be punished, it is not the end of the world. He's a winner. If that means he occasionally steps over the line between right and wrong, than that's what comes with the territory."Steve ClaridgeSteve Claridge believes potentially career-ending challenges are the biggest sin in footballThe leg-breakerVerdict: 'The ultimate sin'The reckless over-the-top, studs-up tackle has been banished in football's rule book at least. But intentionally or not, it still features in the game.The act has the potential to end a career in a second, leaving a player's hopes and dreams in tatters."That's the number one," said Claridge. "The rest, with all due respect, are nothing in comparison. You may as well give up if you're scared what people will say about you in football, but if you're talking of a player intentionally trying to seriously hurt a player in a tackle, that's the one."You can do serious damage to the legs and rob a player of all he has known. It happened to me twice and both times I got sent off for reacting to what had happened to me. Even now when I see someone do something like that I think 'that player has tried to hurt someone, he should not be playing for six months'."(BBC)Bakudaily.az