| flat(adjective, dull, weak, smooth, gentle) |
| flavorless(adjective, dull, weak, plain, mild) |
| fluctuant(adjective, uncertain, nervous, doubtful, shaky) |
| fluctuating(adjective, weak, uncertain, doubtful, hesitant) |
| fly-by-night(adjective, uncertain, nervous, doubtful, shaky) |
| genial(adjective, calm, weak, smooth, soft) |
| gross(adjective, out, lousy, unattractive, hated) |
| halfhearted(adjective, weak, uncertain, doubtful, shaky) |
| halting(adjective, weak, uncertain, doubtful, hesitant) |
| having spring fever(expression, adjective, idiom, dull, idle) |
| heavy(adjective, dull, weak, easy, slow) |
| helpless(adjective, weak, thin, delicate, shaky) |
| hesitant(adjective, weak, uncertain, nervous, doubtful) |
| hesitating(adjective, weak, uncertain, doubtful, hesitant) |
| ho-hum(adjective, calm, weak, smooth, soft) |
| ho hum(expression, adjective, dull, weak, plain) |
| hot-and-cold(adjective, weak, uncertain, doubtful, hesitant) |
| humdrum(adjective, dull, weak, plain, mild) |
| idle(adjective, dull, stupid, weary, apathetic) |
| iffy(adjective, uncertain, nervous, doubtful, shaky) |