| commonplace(adjective, dull, simple, plain, ordinary) |
| conk out(expression, rest, relax, retire, languish) |
| crash(rest, relax, retire, languish, nap) |
| crawl(verb, worry, fail, strain, annoy) |
| creep(noun, bother, drag, nuisance, nonevent) |
| dead(adjective, quiet, simple, flat, clean) |
| deadhead(noun, bother, drag, nuisance, nonevent) |
| debilitate(verb, worry, fail, strain, annoy) |
| dehiscence |
| deject(verb, worry, fail, strain, annoy) |
| dejection(depression, melancholy, gloom, apathy, lethargy) |
| demanding(adjective, dull, boring, tired, tedious) |
| depress(verb, worry, fail, strain, annoy) |
| depression(melancholy, gloom, apathy, lethargy, slump) |
| detachment(noun, melancholy, dullness, apathy, indifference) |
| diddly(adjective, simple, clean, plain, ordinary) |
| difficult(adjective, dull, boring, tired, tedious) |
| disclosure |
| disgust(noun, verb, worry, fail, strain) |
| dishearten(verb, worry, fail, strain, annoy) |