Dictionary definition · sour
noun
- a cocktail made of a liquor (especially whiskey or gin) mixed with lemon or lime juice and sugar
- the taste experience when vinegar or lemon juice is taken into the mouth
- the property of being acidic
verb
- go sour or spoil"The milk has soured"
- make sour or more sour
adjective
- smelling of fermentation or staleness
- having a sharp biting taste
- one of the four basic taste sensations; like the taste of vinegar or lemons
- in an unpalatable state"sour milk"
- inaccurate in pitch"a false (or sour) note"
- showing a brooding ill humor"a dark scowl"
Source: Open English WordNet (CC BY 4.0).