| doubtable(uncertain, doubtful, shaky, dubious, unclear) |
| dynamite(adjective, delicate, uncertain, unstable, doubtful) |
| extent(noun, top, point, line, limit) |
| extremity(noun, top, point, limit, extreme) |
| far-fetched(uncertain, shaky, unclear, unlikely, questionable) |
| fat chance(expression, uncertain, shaky, unclear, unlikely) |
| fishy(uncertain, shaky, vague, dubious, unclear) |
| fluctuant(adjective, uncertain, nervous, doubtful, shaky) |
| fly-by-night(adjective, uncertain, nervous, doubtful, shaky) |
| foot(noun, top, point, limit, extreme) |
| fringing |
| fringy |
| hairy(adjective, delicate, uncertain, unstable, doubtful) |
| hanging by a thread(expression, adjective, idiom, delicate, uncertain) |
| hardscrabble |
| hazardous(adjective, delicate, uncertain, unstable, doubtful) |
| hazy(uncertain, shaky, vague, unclear, ambiguous) |
| head(noun, top, point, limit, extreme) |
| heel(noun, top, point, limit, extreme) |
| hem(noun, edge, trim, border, frontier) |