WordReference Random House Learner's Dictionary of American English © 2026
sour /saʊr, ˈsaʊɚ/USA pronunciation
adj., -er, -est, n.
adj.
n. [countable]
v.
sour•ish, adj.
sour•ly, adv.
sour•ness, n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2026adj.
- having an acid taste resembling that of vinegar;
tart:Lemons taste sour. - made into an acid or acidlike substance by fermentation;
fermented:sour milk. - resembling or suggesting something fermented:Some of the baby's clothes have a sour smell.
- distasteful or disagreeable;
unpleasant:a few sour remarks. - cross;
easily annoyed;
peevish:a sour expression on his face. - Music and Danceoff-pitch;
badly produced:a sour note.
n. [countable]
- Winea cocktail of whiskey and lime or lemon juice.
v.
- to (cause to) become sour or rancid;
spoil: [no object]The milk soured in a few hours.[~ + object]Poor refrigeration will sour stored milk. - to (cause to) become unpleasant or less friendly: [no object]Relations between us soured over the last few years.[~ + object]The war soured our relations.
- to make or cause to become bitter, unhappy, etc.:[~ + object (+ on + object)]All those rejections had soured him (on ever getting another job somewhere).
- [Informal.]
- Idioms go sour, [no object] to become unsatisfactory;
fail:Their marriage has gone sour. - Idioms go sour on, [~ + object] to become enemies with;
turn against:went sour on his family.
sour•ish, adj.
sour•ly, adv.
sour•ness, n. [uncountable]
sour
(souər, sou′ər),USA pronunciation adj., -er, -est, n., v.
adj.
n.
v.i.
v.t.
sour′ish, adj.
sour′ly, adv.
sour′ness, n.
adj.
- having an acid taste, resembling that of vinegar, lemon juice, etc.;
tart. - rendered acid or affected by fermentation;
fermented. - Psychology, Physiologyproducing the one of the four basic taste sensations that is not bitter, salt, or sweet.
- characteristic of something fermented:a sour smell.
- distasteful or disagreeable;
unpleasant. - below standard;
poor. - harsh in spirit or temper;
austere;
morose;
peevish. - Agriculture(of soil) having excessive acidity.
- Chemistry(of gasoline or the like) contaminated by sulfur compounds.
- Music and Danceoff-pitch;
badly produced:a sour note.
n.
- something that is sour.
- Wineany of various cocktails consisting typically of whiskey or gin with lemon or lime juice and sugar and sometimes soda water, often garnished with a slice of orange, a maraschino cherry, or both.
- Chemistryan acid or an acidic substance used in laundering and bleaching to neutralize alkalis and to decompose residual soap or bleach.
v.i.
- to become sour, rancid, mildewed, etc.;
spoil:Milk sours quickly in warm weather. The laundry soured before it was ironed. - to become unpleasant or strained;
worsen;
deteriorate:Relations between the two countries have soured. - to become bitter, disillusioned, or disinterested:I guess I soured when I learned he was married. My loyalty soured after his last book.
- Agriculture(of soil) to develop excessive acidity.
v.t.
- to make sour;
cause sourness in:What do they use to sour the mash? - to cause spoilage in;
rot:Defective cartons soured the apples. - to make bitter, disillusioned, or disagreeable:One misadventure needn't have soured him. That swindle soured a great many potential investors.
- bef. 1000; (adjective, adjectival and noun, nominal) Middle English sure, soure, Old English sūr (origin, originally adjective, adjectival); cognate with German sauer, Dutch zuur, Old Norse sūrr; (verb, verbal) Middle English souren, derivative of the adjective, adjectival
sour′ly, adv.
sour′ness, n.
- 5. bitter. 7. severe, testy, touchy, acrimonious, cross, petulant, crabbed.
- 1. sweet.
'sourness' also found in these entries (note: many are not synonyms or translations):