1. Acidity; sharpness to the taste; tartness; as the sourness of vinegar or of fruit. sourness being one of those simple ideas which one cannot describe.
2. Asperity; harshness of temper. Take care that no sourness and moroseness mingle with our seriousness of mind.
SOUR'-SOP, noun A plant, the annona muricata. The custard apple.