Main Entry: ¹sour

Pronunciation: \ˈsau̇(-ə)r\

Function: adjective

Etymology: Middle English, from Old English sūr; akin to Old High German sūr sour, Lithuanian sūrus salty

Date: before 12th century

1 : causing or characterized by the one of the four basic taste sensations that is produced chiefly by acids <sour pickles> — compare bitter, salt, sweet
2 a (1) : having the acid taste or smell of or as if of fermentation : turned <sour milk> (2) : of or relating to fermentation b : smelling or tasting of decay : rancid, rotten <sour breath> c (1) : bad, wrong <a project gone sour> (2) : hostile, disenchanted <went sour on Marxism>
3 a : unpleasant, distasteful b : cross, sullen c : not up to the usual, expected, or standard quality or pitch
4 : acid in reaction —used especially of soil
5 : containing malodorous sulfur compounds —used especially of petroleum products

— sour·ish \ˈsau̇(-ə)r-ish\ adjective

— sour·ly adverb

— sour·ness noun