sour · pungent (of a smell or taste) strong and usually unpleasant; (of food or smoke) having a pungent smell or taste: · sour (of a taste) bitter like the taste ...

sour · ​[intransitive, transitive] (of relationships, attitudes, people, etc.) to change so that they become less pleasant or friendly than before; to make ...

bitter (of a taste or smell) strong and usually unpleasant; (of food or drink) having a bitter taste. sour (of a taste) like the taste of a lemon or of fruit ...

1[intransitive, transitive] (of relationships, attitudes, people, etc.) to change so that they become less pleasant or friendly than before; ...

The earliest known use of the noun sour is in the 1830s. OED's only evidence for sour is from 1839, in a dictionary by Andrew Ure, chemist.

sour-faced adjective /ˈsaʊə feɪst/ /ˈsaʊər feɪst/ [usually before noun] (of a person) having an unpleasant and unfriendly expression.

sour-faced adjective [usually before noun] (of a person) having a bad-tempered or unpleasant expression.

[only before noun] ​(of food) cooked in a sauce that contains sugar and vinegar or lemon. Chinese sweet-and-sour pork Topics Foodc2.

sour verb (UNPLEASANT) ... to become bad or unpleasant, or cause someone to feel bad or unhappy: [ I ] When the economy soured, donations to the charity dried up.

sweet-and-sour adjective [only before noun] (of food) cooked in a sauce that contains sugar and vinegar or lemon