Definitions

1. adjective

having a sharp, acidic, or unpleasant taste or smell, especially as a result of fermentation or spoilage.

“The spoiled milk had a sour smell and tasted terrible.”

2. noun

a sharp, acidic, or unpleasant taste or smell, especially as a result of fermentation or spoilage.

“The sourness of the lemons added flavor to the salad.”