sour

(noun) a cocktail made of a liquor (especially whiskey or gin) mixed with lemon or lime juice and sugar.

(noun) the taste experience when vinegar or lemon juice is taken into the mouth. Synonyms: sourness, tartness.

(noun) the property of being acidic. Synonyms: sourness, acidity.

(verb) go sour or spoil. Synonyms: turn, ferment, work. Examples: "The milk has soured." "The wine worked." "The cream has turned--we have to throw it out."

(verb) make sour or more sour. Synonyms: acidify, acidulate, acetify.

(adj) smelling of fermentation or staleness. Synonyms: rancid.

(adj) having a sharp biting taste. Synonyms: sour (vs. sweet).

(adj) one of the four basic taste sensations; like the taste of vinegar or lemons.

(adj) in an unpalatable state. Synonyms: off, turned. Examples: "Sour milk."

(adj) inaccurate in pitch. Synonyms: false, off-key. Examples: "A false (or sour) note." "Her singing was off key."

(adj) showing a brooding ill humor. Synonyms: dark, dour, glowering, glum, moody, morose, saturnine, sullen. Examples: "A dark scowl." "The proverbially dour new england puritan." "A glum, hopeless shrug." "He sat in moody silence." "A morose and unsociable manner." "A saturnine, almost misanthropic young genius"- bruce bliven." "A sour temper." "A sullen crowd."