Antonyms for mend

correct, improve, fix:

damage, deteriorate, impair, destroy, kill, miss, weaken, break, harm, worsen, ruin, lose, injure, decline, hurt.

noun:

degenerate, misdiagnose, afflict, sink, wilt, worsen, wither, sicken, languish, harm, aggravate, vandalize, relapse, ruin, mar, enfeeble, deteriorate, flaw, tarnish, wreck, fade, impair, damage, come down, weaken, waste, corrupt, depress, fail, debilitate, regress, enervate, decline, blemish, collapse, vitiate, hurt, debase, ail, spoil, lame, backslide, sap.