ENOUGH IS ENOUGH - "What one has said or done is already excessive. Usually used as an angry response. The proverb has been traced back to about 1375. In 1546, John Heywood included it in his book of proverbs. First attested in the United States in 'The Down-Easters' (1833) by John Neal (1793-1876).1949 'Will: I got a job. Charley: Without pay? What kind of a job is a job without pay? (He rises.) Now, look, kid, enough is enough.' - Arthur Miller, 'Death of a Salesman.'." From "Random House Dictionary of Popular Proverbs and Sayings" by Gregory Y. Titelman (Random House, New York, 1996).
http://www.phrases.org.uk/bulletin_board/10/messages/873.html
Proverbs: Enough is enough
From its older use as an expression of content or satisfaction (cf. enough is as good as a feast), this is now frequently used as a reprimand, warning someone off from persisting in an inappropriate or excessive course of action.
Sens enough is enough (sayd I) here maie we With that one word take end good.
[1546 J. Heywood Dialogue of Proverbs ii. xi. M1]
‘I will descend for no more,’ said the Moor, doggedly; ‘enough is enough for a reasonable man—more is superfluous.’
[1832 W. Irving Alhambra II. 40]
I realize all its merits just as well as you do. But enough is enough.
[1915 T. Dreiser Titan (ed. 3) xlvii. 404]
We all enjoyed your encouraging letter—‘Dear Sir, The bank looks forward to a return to the traditional arrangement whereby you bank with us, rather than vice-versa. Enough is enough.’
[2002 Times 10 Aug. 23]
Idioms: enough is enough
One should be satisfied; stop, there should be no more. For example, No more speeches--enough is enough, or as Robert Southey put it (The Doctor, 1834): "As for money, enough is enough; no man can enjoy more." This expression already appeared in John Heywood's proverb collection of 1546 and is often used as an interjection (first example).
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