| uncool(adjective, inadequate, useless, inappropriate, unhealthy) |
| under the weather(expression, idiom) |
| unelevated |
| unlikely(adjective, inadequate, useless, inappropriate, unhealthy) |
| unmeet(adjective, inadequate, useless, inappropriate, unhealthy) |
| unpromising(adjective, inadequate, useless, inappropriate, unhealthy) |
| unsound(adjective, weak, delicate, ill, sick) |
| unstable(adjective, weak, delicate, ill, sick) |
| unsubstantial(adjective, weak, delicate, ill, sick) |
| unsuitable(adjective, inadequate, useless, inappropriate, unhealthy) |
| unsuited(inadequate, inappropriate, unhealthy, unsuitable, unlikely) |
| used up |
| useless(adjective, inadequate, inappropriate, unhealthy, unsuitable) |
| vacillating(adjective, weak, delicate, ill, sick) |
| valueless(adjective, inadequate, useless, inappropriate, unhealthy) |
| washy |
| wasted |
| wavering(adjective, weak, delicate, ill, sick) |
| weak(adjective, delicate, ill, sick, feeble) |
| wobbly(adjective, weak, delicate, ill, sick) |