regret

Etymology

From Middle English regretten, regreten, from Old French regreter, regrater (“to lament”), from re- (intensive prefix) + *greter, *grater (“to weep”), from Frankish *grātan (“to weep, mourn, lament”), from Proto-Germanic *grētaną (“to weep”), from Proto-Indo-European *ǵʰreh₁d- (“to sound”); and Frankish *greutan (“to cry, weep”), from Proto-Germanic *greutaną (“to weep, cry”), from Proto-Indo-European *gʰrewd- (“to weep, be sad”), equivalent to re- + greet. Cognate with Old High German grāzan (“to cry”), Old English grǣtan (“to weep, greet”), Old English grēotan (“to weep, lament”), Old Norse gráta (“to weep, groan”), Gothic 𐌲𐍂𐌴𐍄𐌰𐌽 (grētan, “to weep”). More at greet.

verb

1. To feel sorry about (a thing that has or has not happened), afterthink: to wish that a thing had not happened, that something else had happened instead.
   He regretted his words.
   Dear humanity, we regret bein' alien bastards, we regret comin' to Earth, and we most definitely regret the Corps just blew up our raggedy-ass fleet! Nov 9 2004, Halo 2 (video game cutscenes), spoken by Avery Johnson (David Scully), Microsoft Studios
2. (more generally) To feel sorry about (any thing).
   I regret that I have to do this, but I don't have a choice.
3. (archaic, transitive) To miss; to feel the loss or absence of; to mourn.
   He more than ever regretted his home, and with increased desire longed to see his family. 1845, The Church of England Magazine, volume 19, page 301

noun

1. Emotional pain on account of something done or experienced in the past, with a wish that it had been different; a looking back with dissatisfaction or with longing.
   What man does not remember with regret the first time he read Robinson Crusoe? 1828, Thomas Macaulay, John Dryden
2. (obsolete) Dislike; aversion.
   Is it a vertue to have some ineffective regrets to damnation, and such a Vertue too, as shall serve to ballance all our vices? 1667, Richard Allestree, The Causes of the Decay of Christian Piety
3. (decision theory) The amount of avoidable loss that results from choosing the wrong action.
   Under squared errorloss we show that there exists unique minimax regret solution for the problem of selecting the threshold. 2002, Bernd Droge, On the Minimax Regret Estimation of a Restricted Normal Mean, and Implications
   Each loss then represents this unavoidable loss plus a regret (loss due to ignorance of Ө). Subtracting these unavoidable losses, we obtain the regret table, Table 1.7, and the average regret table, Table 1.8. 2012, Herman Chernoff, Lincoln E. Moses, Elementary Decision Theory, page 12