| degenerate(verb, decline, weaken, deteriorate, decay) |
| deteriorate(verb, decline, weaken, degenerate, wane) |
| adulterate(verb, decline, weaken, degenerate, deteriorate) |
| alloy(verb, decline, weaken, degenerate, deteriorate) |
| be worse for wear(verb, decline, fail, lower, weaken) |
| break(verb, decline, fail, lower, weaken) |
| corrode(verb, decline, weaken, degenerate, deteriorate) |
| corrupt(verb, decline, weaken, degenerate, deteriorate) |
| crumble(verb, decline, fail, lower, weaken) |
| debase(verb, decline, weaken, degenerate, deteriorate) |
| debilitate(verb, decline, weaken, degenerate, deteriorate) |
| decay(verb, decline, fail, lower, weaken) |
| decline(verb, weaken, degenerate, deteriorate, decay) |
| decompose(verb, decline, fail, lower, weaken) |
| degrade(verb, decline, weaken, degenerate, deteriorate) |
| deprave(verb, decline, weaken, degenerate, deteriorate) |
| depreciate(verb, decline, weaken, degenerate, deteriorate) |
| descend(verb, decline, weaken, degenerate, deteriorate) |
| disimprove(verb, decline, fail, lower, weaken) |
| disintegrate(verb, decline, fail, lower, weaken) |