| suppurate(verb, decline, weaken, lessen, degenerate) |
| turn(verb, decline, weaken, lessen, degenerate) |
| turn out badly(verb, expression, idiom, decline, fall) |
| waste away(verb, expression, phrasal verb, decline, weaken) |
| wilt(verb, fail, weaken, degenerate, deteriorate) |
| abate(verb, drop, fall, fail, diminish) |
| adulterate(verb, decline, weaken, degenerate, deteriorate) |
| alloy(verb, decline, weaken, degenerate, deteriorate) |
| atrophy(verb, decline, degenerate, deteriorate, worsen) |
| be worse for wear(verb, decline, fail, lower, weaken) |
| become less(verb, expression, drop, fall, fail) |
| become worse(verb, expression, decline, fail, lower) |
| cave in |
| cheapen(verb, drop, fall, fail, diminish) |
| come apart |
| conk out |
| corrupt(verb, decline, weaken, degenerate, deteriorate) |
| debase(verb, decline, weaken, degenerate, deteriorate) |
| debilitate(verb, decline, weaken, degenerate, deteriorate) |
| decay(verb, drop, decline, fall, fail) |