sour(redirected from turn sour)
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1. made acid or bad, as in the case of milk or alcohol, by the action of microorganisms
2. (esp of the weather or climate) harsh and unpleasant
3. (of oil, gas, or petrol) containing a relatively large amount of sulphur compounds
4. Chiefly US any of several iced drinks usually made with spirits, lemon juice, and ice
Containing large amounts of malodorous sulfur compounds (such as mercaptans or hydrogen sulfide), as in crude oils, naphthas, or gasoline.