| spasmodic(adjective, characteristic, doubt, instability) |
| suspect(adjective, characteristic, doubt, instability) |
| suspicious(adjective, characteristic, doubt, instability) |
| temperamental(adjective, characteristic, doubt, instability) |
| thorny(adjective, characteristic, doubt, instability) |
| threatening(adjective, characteristic, doubt, instability) |
| timid(adjective, characteristic, fear, cowardice) |
| timorous(adjective, characteristic, fear, cowardice) |
| transformable(adjective, characteristic, doubt, instability) |
| transitional(adjective, characteristic, doubt, instability) |
| treacherous(adjective, characteristic, doubt, instability) |
| unconfirmed(adjective, characteristic, doubt, instability) |
| undecided(adjective, characteristic, doubt, instability) |
| unreasonable(adjective, characteristic, doubt, instability) |
| unreliable(adjective, characteristic, doubt, instability) |
| unsafe(adjective, characteristic, doubt, instability) |
| unsteady(adjective, characteristic, doubt, instability) |
| unsure(adjective, characteristic, doubt, instability) |
| up and down(expression, characteristic, doubt, instability) |
| up for grabs(expression, characteristic, doubt, instability) |