| unfirm(weak, unstable, unsettled, shaky, unsteady) |
| unglued(adjective, upset, excited, anxious, nervous) |
| unsound(weak, unstable, feeble, unsettled, trembling) |
| unsure(adjective, weak, unstable, unsettled, unsteady) |
| upheaval(noun, fit, stir, shake, protest) |
| upset(adjective, agitated) |
| upsetting(verb, agitating) |
| uptight(adjective, upset, excited, anxious, nervous) |
| used(feeble, dilapidated, debilitated, deteriorated, decaying) |
| vacillant |
| vacillating(weak, unstable, unsettled, unsteady, trembling) |
| vacillation(noun, quiver, shudder, trembling, tremor) |
| velar |
| volcanic activity(expression, idiom, trembling, tremor, quake) |
| wasted(feeble, frail, flimsy, dilapidated, debilitated) |
| watchful(adjective, upset, excited, anxious, nervous) |
| wave motion |
| waving |
| weak(adjective, unstable, sick, feeble, unsettled) |
| weakly(feeble, frail, flimsy, dilapidated, debilitated) |