1. (v. t.) To make worse; to degenerate; to make inferior in quality or value; to impair; as, to deteriorate the mind\.

2. (v. i.) To grow worse; to be impaired in quality.

agent provocateur aggravate alter ameliorate amplify annoy augment be changed be converted into be renewed bottom out break build up change checker chop chop and change come about come around come down come round crumble damage debilitate decay decline decompose deepen degenerate degrade depreciate descend deviate dilapidate disimprove disintegrate diverge diversify embitter endamage enhance enlarge erode exacerbate exasperate fade fall back flag flop get worse go downhill go to pot grow worse harm haul around have a comedown heat up heighten hit rock bottom hot up hurt impair improve increase injure intensify irritate jibe languish lessen let down magnify make acute make worse mar meliorate mitigate modulate mutate provoke put back reach the depths regress relapse retrograde retrogress revive rot sharpen shift sicken sink slacken slide slip slip back sour spoil swerve tack take a turn touch bottom turn turn aside turn into turn the corner undergo a change undermine vary veer warp weaken worsen