1. becomes or makes something become sour in taste
2. becomes or makes something become unpleasant or unfriendly

1. cocktails made with liquor, lemon or lime juice, and sugar

Examples

• The milk sours quickly in hot weather.
• His attitude sours whenever he’s tired.
• The relationship soured after the argument.
• Heat sours the cream if left out too long.
• The bartender makes excellent whiskey sours.
• She ordered two gin sours for the table.
• Success can sour if it comes too easily.