• (America) IPA: /ˈsaʊ(ə)ɹ/
• (RP) IPA: /ˈsaʊə/

sour (comparative sourer, superlative sourest)

1. Having an acidic, sharp or tangy taste.

   Lemons have a sour taste.

   • 1626, Francis Bacon, Sylva Sylvarum, Or, A Naturall Historie: In Ten Centuries

     All sour things, as vinegar, provoke appetite.

   • 2018 May 16, Adam Rogers, Wired, "The Fundamental Nihilism of Yanny vs. Laurel ↗":

     A few types of molecules get sensed by receptors on the tongue. Protons coming off of acids ping receptors for "sour." Sugars get received as "sweet." Bitter, salty, and the proteinaceous flavor umami all set off their own neural cascades.

2. Made rancid by fermentation, etc.

   Don't drink that milk; it's turned sour.

3. Tasting or smelling rancid.

   His sour breath makes it unpleasing to talk to him.

4. (of a person's character) Peevish or bad-tempered.

   He gave me a sour look.

   • c. 1591–1592, William Shakespeare, “The Third Part of Henry the Sixt, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, OCLC 606515358 ↗, [Act III, scene i]:

     He was a scholar […] / Lofty and sour to them that loved him not, / But to those men that sought him sweet as summer.

5. (of soil) Excessively acidic and thus infertile.

   sour land

   a sour marsh

6. (of petroleum) Containing excess sulfur.

   sour gas smells like rotten eggs

7. Unfortunate or unfavorable.
   • 1613, William Shakespeare; [John Fletcher], “The Famous History of the Life of King Henry the Eight”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, OCLC 606515358 ↗, [Act IV, scene ii]:

     Let me embrace thee, sour adversity

8. (music) Off-pitch, out of tune.

• (petroleum) sweet

• French: aigre, sur
• German: sauer
• Italian: agro
• Portuguese: azedo
• Russian: ки́слый
• Spanish: agrio, ácido

• French: rance, tourné
• German: sauer, sauer vergoren, gesäuert
• Portuguese: coalhado
• Spanish: agrio, acedo

• French: rance
• German: sauer, ranzig
• Portuguese: rançoso
• Spanish: agrio

• French: acerbe, acariâtre, revêche
• German: sauer, angesäuert, angesäuert
• Portuguese: carrancudo

• German: sauer
• Portuguese: ácido

sour

1. The sensation of a sour taste.

2. A drink made with whiskey, lemon or lime juice and sugar.

3. (by extension) Any cocktail containing lemon or lime juice.
4. A sour or acid substance; whatever produces a painful effect.
5. The acidic solution used in souring fabric.

• German: Säure
• Portuguese: azedume

• German: Whiskey Sauer

sour (sours, present participle souring; past soured, past participle soured)

1. (transitive) To make sour.

   Too much lemon juice will sour the recipe.

2. (intransitive) To become sour.
   • RQ

     So the sun's heat, with different powers, / Ripens the grape, the liquor sours.

3. (transitive) To spoil or mar; to make disenchanted.
   • 1611 April (first recorded performance)​, William Shakespeare, “The Tragedie of Cymbeline”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, OCLC 606515358 ↗, [Act V, scene v]:

     To sour your happiness I must report, / The queen is dead.

   • 1749, Henry Fielding, The History of Tom Jones, a Foundling. In Six Volumes, volume (please specify ), London: Printed by A[ndrew] Millar, […], OCLC 928184292 ↗:

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     He was prudent and industrious, and so good a husbandman, that he might have led a very easy and comfortable life, had not an arrant vixen of a wife soured his domestic quiet.

4. (intransitive) To become disenchanted.

   We broke up after our relationship soured.

5. (transitive) To make (soil) cold and unproductive.
6. To macerate (lime) and render it fit for plaster or mortar.
7. (transitive) To process (fabric) after bleaching, using hydrochloric acid or sulphuric acid to wash out the lime.

• Italian: inasprire
• Portuguese: azedar

• German: säuern, versäuern, sauer vergären
• Portuguese: azedar

• Italian: deteriorarsi, degenerare