sour

US /saʊr/
UK /saʊr/
"sour" picture
1.

having an acidic taste like lemon or vinegar

:
The lemonade was too sour for my liking.
She made a face after tasting the sour candy.
2.

unpleasant or unfriendly

:
The meeting ended on a sour note.
Their relationship turned sour after the argument.
1.

become unpleasant, acrimonious, or unfriendly

:
Their friendship began to sour after the misunderstanding.
The milk will sour if left out of the fridge.