sour

Universal Words adjective, verb adjective 1 having a bitter taste like the taste of a lemon or of fruit that is not ripe: sour apples * a sour flavour OPPSWEET seealsoSWEET-AND-SOUR 2 (especially of milk) having an unpleasant taste or smell because it is not fresh: to turn / go sour * sour milk / cream * a sour smell 3 (of people) not cheerful; bad-tempered and unpleasant: a sour and disillusioned woman * a sour face / smile * The meeting ended on a sour note with several people walking out. sourly adverb: 'Who asked you?' he said sourly. sourness noun [U]: the sourness of the fruit * his increasing sourness IDIOMS go / turn sour to stop being pleasant or satisfactory: Their relationship soon went sour. sour grapes (saying) used to show that you think sb is jealous and is pretending that sth is not important: He said he didn't want the job anyway, but that's just sour grapes. verb 1 (of relationships, attitudes, people, etc.) to change so that they become less pleasant or friendly than before; to make sth do this: [V] The atmosphere at the house soured. * [VN] The disagreement over trade tariffs has soured relations between the two countries. 2 [V, VN] if milk sours or if sth sours it, it becomes sour and has an unpleasant taste or smell