Emily Dickinson Lexicon

SOUR'NESS, n.

1. Acidity; sharpness to the taste; tartness; as, the sourness of vinegar or of fruit. Sourness being one of those simple ideas which one can not, describe. – Arbuthnot.
2. Asperity; harshness of temper. Take care that no sourness and moroseness mingle with our seriousness of mind. – Nelson.