| enfeeble(verb, hurt, ruin, destroy, blow) |
| fail(verb, decline, lower, weaken, lessen) |
| fester(verb, decay, decompose, molder) |
| get worse(expression, decline, weaken, lessen, degenerate) |
| go bad(verb, expression, decline, weaken, lessen) |
| go to seed(verb, expression, idiom, decline, use) |
| go to the dogs(verb, expression, idiom, decline, reduce) |
| hit rock bottom(expression, idiom, decline, weaken, lessen) |
| hit the skids(verb, expression, idiom, decline, fail) |
| mildew(verb, decline, weaken, lessen, degenerate) |
| mold(verb, decline, weaken, lessen, degenerate) |
| mortify(verb, decline, weaken, lessen, degenerate) |
| pejorate(verb, decline, weaken, lessen, degenerate) |
| perish(verb, decline, blow, weaken, lessen) |
| pollute(verb, break, dull, decline, hurt) |
| putresce(verb, decline, weaken, lessen, degenerate) |
| reach depths(expression, decline, weaken, lessen, degenerate) |
| sap(verb, decline, hurt, ruin, destroy) |
| shrivel(verb, decline, weaken, lessen, degenerate) |
| sicken(verb, decline, pain, weaken, lessen) |