1. (superl.) Having an acid or sharp, biting taste, like vinegar, and the juices of most unripe fruits; acid; tart.

2. (superl.) Changed, as by keeping, so as to be acid, rancid, or musty, turned.

3. (superl.) Disagreeable; unpleasant; hence; cross; crabbed; peevish; morose; as, a man of a sour temper; a sour reply.

4. (superl.) Afflictive; painful.

5. (superl.) Cold and unproductive; as, sour land; a sour marsh.

6. (n.) A sour or acid substance; whatever produces a painful effect.

7. (v. t.) To cause to become sour; to cause to turn from sweet to sour; as, exposure to the air sours many substances.

8. (v. t.) To make cold and unproductive, as soil.

9. (v. t.) To make unhappy, uneasy, or less agreeable.

10. (v. t.) To cause or permit to become harsh or unkindly.

11. (v. t.) To macerate, and render fit for plaster or mortar; as, to sour lime for business purposes.

12. (v. i.) To become sour; to turn from sweet to sour; as, milk soon sours in hot weather; a kind temper sometimes sours in adversity.

abrupt absonant acerb acerbate acerbic acerbity acescency acescent acetify acid acidic acidify acidity acidulant acidulate acidulated acidulent acidulous acidulousness acrid acrimonious aftertaste agent provocateur aggravate amaroidal amplify annoy asperous astringent atonal augment bad bad-tempered bilious biting bitter bitter as gall blown bread-and-butter pickle brusque build up cacophonous caustic chokecherry choleric churlish coarse crab crab apple crabbed crabby cracked cranky cross crusty curdle curdled curt cutting deepen deteriorate diaphonic dill pickle disagreeable disconsonant discontented discordant disenchant disharmonic disharmonious dislikable displeasing dissonant distasteful dry dryness dyspeptic edgy embitter embittered enhance enlarge envenom escharotic exacerbate exasperate ferment fermented flat flavor frowy gamy gloomy go bad go off gone off grating green green apple greenness grouchy gust hard harsh heat up heighten high hot up hyperacidity ill-natured ill-tempered immelodious impatient increase inharmonic inharmonious intensify irritate irritating jaundiced keen lemon lime magnify make acute make worse mordant morose musicless nasty nonmelodious nose-tickling off off-key off-tone out of pitch out of tone out of tune palate peeve peevish penetrating petulant pickle pickled piercing piquant poignant provoke pungency pungent rancid rank raucous reechy relish rough salt sapidity sapor savor savoriness sec severe sharp sharpen shrill smack snappish sour as vinegar sour balls sour cream sour grapes sour pickle sour-tempered sourdough soured sourish sourishness sourness spoil spoiled spoilt stale stinging stomach strident strong subacidity sullen sweet tainted tang tart tartish tartishness tartness taste terrible testy thankless tongue tooth trenchant tuneless turn turn sour turned ugly unalluring unappealing unappetizing unattractive undelectable undelicious undesirable unengaging unenjoyable unharmonious uninviting unlikable unmelodious unmusical unpalatable unpleasant unpleasing unripe unripeness unsavory unsweet unsweetened unsweetness untasteful untunable untuned untuneful unwelcome verjuice vex vinegar vinegariness vinegarish vinegarishness vinegary vitriolic worsen yogurt