Sour, v. t. [AS. s�rian to sour, to become sour.] 1. To cause to become sour; to cause to turn from sweet to sour; as, exposure to the air sours many substances.
So the sun's heat, with different powers,
Ripens the grape, the liquor sours. Swift.
2. To make cold and unproductive, as soil. Mortimer.
3. To make unhappy, uneasy, or less agreeable.
To sour your happiness I must report,
The queen is dead. Shak.
4. To cause or permit to become harsh or unkindly. “Souring his cheeks.” Shak.
Pride had not sour'd nor wrath debased my heart. Harte.
5. To macerate, and render fit for plaster or mortar; as, to sour lime for business purposes.