| backslide(verb, drop, decline, fall, fail) |
| be defeated(verb, decline, fall, fail, slip) |
| be demoted(verb, decline, fall, fail, slip) |
| be found lacking(verb, decline, fall, fail, slip) |
| be impaired(verb, decline, weaken, lessen, degenerate) |
| be in vain(verb, decline, fall, fail, slip) |
| be ruined(verb, decline, fall, fail, slip) |
| be unsuccessful(verb, decline, fall, fail, slip) |
| become contaminated(verb, expression, decline, weaken, lessen) |
| blight(verb, decline, weaken, lessen, degenerate) |
| blunder(verb, decline, fall, fail, slip) |
| break(verb, decline, fall, fail, lower) |
| break down(verb, expression, phrasal verb, decline, fall) |
| break up(verb, expression, phrasal verb, decline, weaken) |
| come to naught(verb, expression, idiom, decline, fall) |
| come to nothing(verb, expression, idiom, decline, fall) |
| corrode(verb, decline, fail, lower, weaken) |
| curdle(verb, decline, weaken, lessen, degenerate) |
| decompose(verb, decline, fail, lower, weaken) |
| defile(verb, decline, weaken, lessen, degenerate) |