sour

sour — adjective

1. a quality of food or drink that gives a sharp, tight feeling on your tongue, lik

1.adjectiveA2
Definition

a quality of food or drink that gives a sharp, tight feeling on your tongue, like the taste you get from a lemon or from vinegar — the opposite of sweet.

Example

The lemonade was too sour for Nia, so she added a spoonful of sugar.

These pickles have a pleasant sour flavour that goes well with grilled fish.

collocation: sour flavour

Common collocations
  • sour taste
  • sour flavour
  • sour candy
  • sweet and sour
  • sour fruit
Synonyms
  • tart

    sharp-tasting but less harsh than sour; often used for fruits like apples or cherries

  • tangy

    pleasantly sharp, with a more positive feeling than sour

  • acidic

    more technical; describes foods with a high acid content

Antonyms
  • sweet

    the taste that is the opposite of sour, like sugar or honey

Usage Note

Often paired with 'sweet' as an opposite: 'sweet and sour' is a common pairing in cooking.

Common Mistakes

The apple tastes sourly.
The apple tastes sour.
'sour' is an adjective, not an adverb, after linking verbs like 'taste.'

2. describes a person who is unfriendly, easily annoyed, or always in a bad mood.

2.adjectiveB1
Definition

describes a person who is unfriendly, easily annoyed, or always in a bad mood.

Example

After losing his job, Stefan became sour and stopped talking to his friends.

Tara gave a sour look when her brother interrupted her favourite programme.

phrase: a sour look

Common collocations
  • sour mood
  • sour expression
  • sour face
  • sour look
  • turn sour
Synonyms
  • grumpy

    easily annoyed, more informal than sour

  • cross

    mildly angry; common in British English

  • sullen

    silently bad-tempered, showing resentment without speaking

Antonyms

Common Mistakes

She gave me a sourly glance.
She gave me a sour glance.
'sour' modifies the noun 'glance' directly; an adverb is not correct here.

3. describes food or drink that, due to age or lack of proper storage, develops a s

3.adjectiveB1
Definition

describes food or drink that, due to age or lack of proper storage, develops a sharp, stale flavour and a bad smell — for example, milk kept past its use-by date.

Example

Heather poured the sour milk down the sink and opened a fresh carton.

collocation: sour milk

The bread had a sour smell, so Constanza threw it in the bin.

Common collocations
  • go sour
  • turn sour
  • sour milk
  • sour cream
  • sour smell
Synonyms
  • off

    slightly spoiled; common with milk in British English

  • rancid

    strongly spoiled, especially for oils, fats, and nuts

  • curdled

    separated into lumps, of milk or eggs that have gone bad

Antonyms
  • fresh

    newly produced or picked, not spoiled

Usage Note

Distinguish from sense 1 (ACIDIC TASTE): sense 1 describes a natural sharp taste in fresh food; sense 3 describes an unwanted change caused by spoilage.

Common Mistakes

The fresh milk is sour.
This fresh milk tastes slightly sour naturally.
'sour' for spoilage implies the food has gone bad, not that it has a natural acidic taste.
Idioms

go/turn sour

idiom

When something becomes unpleasant or stops working well.

The business deal went sour after they disagreed on the price.

Did the friendship turn sour after that argument?

sour grapes

idiom

Used to describe when someone pretends not to want something because they cannot have it.

Mina said the prize was ugly, but that's just sour grapes.

Is his criticism of the award really sour grapes?

sour — verb

sour — noun

Word family

  • sourly
    adverbB2
  • sourness
    nounB2
  • sourish
    adjectiveC1
  • sours
    nounB2

Synonym discussion

Sense: adjective/1

These four words all describe a sharp, acidic taste but differ in tone and usage. 'Tart' (B1) is milder than 'sour' and usually positive — you would say a cherry pie is 'pleasantly tart' but not 'sour' unless it had gone bad. 'Tangy' (B1) is informal and positive, suggesting a refreshing sharpness, as in 'a tangy lemon dressing.' 'Acidic' (B2) is more technical and neutral, used in food science or chemistry contexts; it can sometimes sound negative when describing everyday food ('the sauce was too acidic'). 'Sharp' (A2) is the broadest of the four and can refer to any intense taste or smell, not just acidic ones. For example: 'This cheese has a sharp, tangy flavour.' A learner choosing between these words should consider register: 'tangy' for casual, positive descriptions; 'tart' for fruit; 'acidic' for technical or critical observations; and 'sharp' for intensity more broadly.

tarttangyacidic ↗sharp ↗

Common collocations

Nouns

Adverbs

  • completely sour
  • slightly sour
  • rather sour
  • pleasantly sour
  • turned sour

Phrases

Prepositions

  • sour to the taste
  • sour from the heat

Etymology

Proto-GermanicOld EnglishMiddle EnglishEnglish

The word 'sour' comes from Old English 'sūr', which traces back to a Proto-Germanic root meaning 'sharp or acidic.' This ancient root is shared with Dutch 'zuur' and German 'sauer.' The original sense always described taste, but by the 1200s it was already being used figuratively to describe a person's unpleasant mood or expression. The verb form appeared around the 1300s, first for food spoiling and later for relationships going bad.