become worse

crumble decline degrade depreciate disintegrate ebb fade fail fall apart languish lessen lower regress sink slide undermine weaken worsen

adulterate alloy break corrode corrupt debase debilitate decompose deprave descend flag impair injure lapse mar pervert retrograde retrogress rot skid spoil vitiate

be worse for wear disimprove go downhill go to pieces go to pot go to the dogs hit the skids lose it lose quality wear away

approve compliment elevate grow improve increase laud praise raise rise strengthen

aid assist build clean cleanse clear cure fix heal help join mend purify put together

construct develop get better