sour

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Having a taste characteristic of that produced by acids; sharp, tart, or tangy.
• adjective Made acid or rancid by fermentation.
• adjective Having the characteristics of fermentation or rancidity; tasting or smelling of decay.
• adjective Bad-tempered and morose; peevish.
• adjective Displeased with something one formerly admired or liked; disenchanted.
• adjective Not measuring up to the expected or usual ability or quality; bad.
• adjective Not having the correct or properly produced pitch.
• adjective Of or relating to excessively acid soil that is damaging to crops.
• adjective Containing excessive levels of sulfur compounds, carbon dioxide, or both. Used of oil and natural gas.
• adjective Containing excessive levels of peroxides. Used of gasoline.
• noun The sensation of sour taste, one of the four primary tastes.
• noun Something sour.
• noun A mixed drink made especially with whiskey, lemon or lime juice, sugar, and sometimes soda water.
• transitive & intransitive verb To make or become sour.
• transitive & intransitive verb To make or become disagreeable, disillusioned, or disenchanted.

from The Century Dictionary.

• Sourly; bitterly.
• noun In drenching or puering skins, the old liquor which has become sour or turned.
• To become sour; become acid; acquire the quality of tartness or pungency to the taste, as by fermentation: as, cider sours rapidly in the rays of the sun.
• To become peevish, crabbed, or harsh in temper.
• To become harsh, wet, cold, or unkindly to crops: said of soil.
• To make sour; make acid; cause to have a sharp taste, especially by fermentation.
• To make harsh, crabbed, morose, or bitter in temper; make cross or discontented; embitter; prejudice.
• To make harsh, wet, cold, or unkindly to crops: said of soil.
• In bleaching, etc., to treat with a dilute acid.
• To macerate and render fit for plaster or mortar, as lime.
• Having an acid taste; sharp to the taste; tart; acid; specifically, acid in consequence of fermentation; fermented, and thus spoiled: as, sour bread; sour milk.
• Harsh of temper; crabbed; peevish; austere; morose: as, a man of a sour temper.
• Afflictive; hard to bear; bitter; disagreeable to the feelings; distasteful in any manner.
• Expressing discontent, displeasure, or peevishness: as, a sour word.
• Cold; wet; harsh; unkindly to crops: said of soil.
• Coarse: said of grass.
• Synonyms Acetous, acetose.
• 2 and
• Cross, testy, waspish, snarling, cynical.
• noun Something sour or acid; something bitter or disagreeable.
• noun Dirt; filth.
• noun An acid punch.
• noun In bleaching and dyeing:
• noun A bath of buttermilk or sour milk, or of soured bran or rye-flour, used by primitive bleachers.
• noun A weak solution of sulphuric or hydrochloric acid, used for various purposes. Compare souring, 5.

from the GNU version of the Collaborative International Dictionary of English.

• noun A sour or acid substance; whatever produces a painful effect.
• transitive verb To cause to become sour; to cause to turn from sweet to sour.
• transitive verb To make cold and unproductive, as soil.
• transitive verb To make unhappy, uneasy, or less agreeable.
• transitive verb To cause or permit to become harsh or unkindly.
• transitive verb To macerate, and render fit for plaster or mortar.
• intransitive verb To become sour; to turn from sweet to sour