definition of
sour

[1] #1 sour v. [turn, ferment, work] go sour or spoil; "The milk has soured"; "The wine worked"; "The cream has turned--we have to throw it out". wn

[2] #2 sour s. [rancid] smelling of fermentation or staleness. wn

[3] #3 sour v. [acidify, acidulate, acetify] make sour or more sour. wn

[4] #4 sour n. a cocktail made of a liquor (especially whiskey or gin) mixed with lemon or lime juice and sugar. wn

[5] #5 sour n. [sourness, tartness] the taste experience when vinegar or lemon juice is taken into the mouth. wn