Answering something Web brought up formerly, a "tactical fault" is not cheating. If the rules of a game contain a measure against a certain behaviour ( a penalty kick for a fault committed eg) then applying that behaviour (committing the fault) because it grants (or it is thought to grant) a tactical advantage is just using the game rules at one's advantage, with no deception involved. It's like parking in a street where you are required to pay a parking ticket without paying it, because you know that the fine you get from not paying the ticket is lower than the amount you are required to pay. One is willing to pay the due fine as it is his right to do. Now, if the same guy was placing a counterfeit parking ticket behind the windscreen, that would be cheating (and I guess a crime too).
Cheating is a deceitful behaviour aimed at getting a personal advantage, whether it involves breaking of rules or not. In life there are no rules to follow (I'm not saying in society, mind me) and yet one can deceive someone else, just by misrepresenting the truth in order to get a personal advantage.
Differently from what the failed expert of word usage claims (and actually diametrically opposed to his false and unfounded claims), deception is always entailed in cheating while the breaking of rules is involved only in determinate circumstances (those environments where behaviour is regulated by rules, like in games).
Cheat: verb
1 [no object] act dishonestly or unfairly in order to gain an advantage:she always cheats at cards
[with object] gain an advantage over or deprive of something by using unfair or deceitful methods; defraud:he had cheated her out of everything she had
informal be sexually unfaithful:his wife was cheating on him
2 [with object] avoid (something undesirable) by luck or skill:she cheated death in a spectacular crash
Dishonesty: noun (plural dishonesties)
[mass noun]: deceitfulness shown in someone’s character or behaviour:the dismissal of thirty civil servants for dishonesty and misconduct
[count noun]: a fraudulent or deceitful act:they are tackling the divisions and dishonesties on the campus
Deceit[mass noun]
the action or practice of deceiving someone by concealing or misrepresenting the truth:a web of deceit
hypocrisy and deceit were anathema to her
[count noun] :a series of lies and deceits