|Origin:||acide, from Latin acidus, from acere 'to be sour'|
having a sharp sour taste [= bitter]:
a juicy apple with a slightly acid flavour
an acid remark uses humour in an unkind way to criticize someone:
I was expecting another of his acid remarks, but he remained silent.
a way of finding out whether something is as good as people say it is, whether it works, or whether it is true:
People ask if the team is good enough. This match will be the acid test.
an acid soil does not contain much lime1 (3):
Blueberry bushes need a very acid soil.
—acidity noun [uncountable]