acidity

noun

1. (countable, uncountable)The quality or state of being acid.
2. (countable, uncountable)Sourness; tartness; sharpness to the taste.

   “the acidity of lemon juice”

   “Empty stomachs lead to acidity and leave a sour taste in the mouth.”

3. (countable, uncountable)Excessive acid quality, as in gastric secretions.
4. (countable, figuratively, uncountable)A caustic, sour, biting, or bitter quality.

   “"What shall we call it?" he asked. "Why should you not take the chance of perpetuating your own name?" said Summerlee, with his usual touch of acidity.”

   “It was a brave, good speech, a speech from that staunch and strong spirit which lay behind all the acidities and angularities of the old zoologist.”