Other forms: cheating, cheated, cheats
To cheat is to break the rules secretly in order to win or pass. Cheat in an exam, cheat at cards, he was caught cheating.
The preposition depends on the setting: cheat in an exam, cheat at a game, cheat on a test in American English. Cheat on somebody is different again and means to be unfaithful to a partner, which is one of the commonest uses in speech. As a noun, a cheat is the person, and in games a cheat is also a code that gives an unfair advantage. Note cheat sheet, meaning a summary of key facts, which is now used with no dishonesty implied at all.
1verbcheatTo break the rules secretly in order to gain an advantage.
“He cheated in the first exam and was caught in the second.”
2verbunfaithfulTo be unfaithful to a partner.
“She found out he had been cheating and left the same week.”
3nounnounSomebody who cheats.
“Nobody wants to play with a cheat.”
Too few real examples of this word to estimate which sense is commonest.
cheat is a way of breaking rules.
Cheat is a shortening of escheat, a legal term for property falling to the crown when somebody died without heirs. The officials who managed escheats had such a reputation that their job title became the word for fraud.
LL.
*excadēre — fall away, fall out
Old French
escheat
Middle English
achetan
English, today
cheat
Built from
Verb from Middle English achetan, variant of escheten, from Old French escheat, past participle of escheoir, escheoiter, from LL. excadēre (“fall away, fall out”), from ex- + cadere. Displaced native beswīcan. Noun from verb and/or Middle English chete, aphetic form of achete, escheat, eschete (“the reversion of property to the state”), from Anglo-Norman eschete and Old French eschet, escheit, escheoit (“that which falls to one”), past participle of escheoir (“to fall”) (modern French échoir), from LL. excadēre (“fall away, fall out”), from ex- + cadere. a doublet of escheat.
Etymology from Wiktionary, CC BY-SA