See deteriorate in Webster's New World Roget's A-Z Thesaurus II
verb
To become lower in quality, character, or condition:
atrophy, decline, degenerate, descend, retrograde, sink, worsen. Idioms: go bad, go to pot, go to seed , go to the dogs. See betterTo lose strength or power:
decline, degenerate, fade, fail, flag2, languish, sink, wane, waste (away), weaken. (Informal) fizzle (out). Idioms: go downhill, hit the skids. See increase, strongTo become or cause to become rotten or unsound:
break down, decay, decompose, disintegrate, molder, putrefy, rot, spoil, taint, turn. Idioms: go bad, go to pot, go to seed. See better, thrive
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