The Oxford Thesaurus An A-Z Dictionary of Synonyms - deterioratev.

1) worsen, decline, degenerate, degrade, spoil, worsen, get worse, depreciate, slip, slide, Colloq go to pot, go to the dogs, go downhill: We have watched their relationship deteriorate over the years. 2) decay, decline, disintegrate, fall apart, decompose, crumble, erode: The building slowly deteriorated and is now uninhabitable.