• Having an acid or sharp, biting taste, like vinegar, and the juices of most unripe fruits; acid; tart. • Changed, as by keeping, so as to be acid, rancid, or musty, turned. • Disagreeable; unpleasant; hence; cross; crabbed; peevish; morose; as, a man of a sour temper; a sour reply. • Afflictive; painful. • Cold and unproductive; as, sour land; a sour marsh. • A sour or acid substance; whatever produces a painful effect. • To cause to become sour; to cause to turn from sweet to sour; as, exposure to the air sours many substances. • To make cold and unproductive, as soil. • To make unhappy, uneasy, or less agreeable. • To cause or permit to become harsh or unkindly. • To macerate, and render fit for plaster or mortar; as, to sour lime for business purposes. • To become sour; to turn from sweet to sour; as, milk soon sours in hot weather; a kind temper sometimes sours in adversity.