Etymology
Advertisement
mens rea 

"state of mind accompanying an act which condemns the perpetrator to criminal punishment," Latin, literally "guilty mind;" from mens "mind," from PIE root *men- (1) "to think."

Related entries & more 
Advertisement
nolo contendere 

Latin, literally "I do not wish to contend." Latin nolo is first person singular present indicative of nolle "be unwilling." In criminal law, a plea by the defendant that admits no guilt but subjects the defendant to judgment. In effect, a guilty plea, but it allows the pleader to deny the truth of the charges in a collateral proceeding.

Related entries & more 
cop out 

by 1942, noun ("a cowardly escape, an evasion") and verb ("sneak off, escape, give up without trying"), American English slang, perhaps from cop a plea (c. 1925) "plead guilty to lesser charges," which is probably from northern British slang cop "to catch" (a scolding, etc.); as in cop a feel "grope someone" (1930s); see cop (v.). Sense of "evade an issue or problem" is from 1960s.

Related entries & more 
black sheep (n.)
by 1822 in figurative sense of "member of some group guilty of offensive conduct and unlike the other members," supposedly because a real black sheep had wool that could not be dyed and thus was worth less. But one black sheep in a flock was considered good luck by shepherds in Sussex, Somerset, Kent, Derbyshire. First known publication of Baa Baa Black Sheep nursery rhyme is in "Tommy Thumb's Pretty Song Book" (c. 1744).
Related entries & more