cheat (v.) Look up cheat at Dictionary.com
mid-15c., "to escheat," a shortening of Old French escheat, legal term for revision of property to the state when the owner dies without heirs, literally "that which falls to one," past participle of escheoir "happen, befall, occur, take place; fall due; lapse (legally)," from Late Latin *excadere "fall away, fall out," from Latin ex- "out" (see ex-) + cadere "to fall" (see case (n.1)). Also compare escheat. The royal officers evidently had a low reputation. Meaning evolved through "confiscate" (mid-15c.) to "deprive unfairly" (1580s). To cheat on (someone) "be sexually unfaithful" first recorded 1934. Related: Cheated; cheating.
cheat (n.) Look up cheat at Dictionary.com
late 14c., "forfeited property," from cheat (v.). Meaning "a deceptive act" is from 1640s; earlier, in thieves' jargon, it meant "a stolen thing" (late 16c.), and earlier still "dice" (1530s). Meaning "a swindler" is from 1660s.