| fitful(careless, unstable, unreasonable, unpredictable, changeable) |
| flaky(careless, unstable, unreasonable, unpredictable, changeable) |
| flawless(adjective, fastidious) |
| flighty(careless, unstable, unreasonable, unpredictable, changeable) |
| forbidding(adjective, tough, severe, firm, harsh) |
| freakish(careless, unstable, unreasonable, unpredictable, changeable) |
| fretting(adjective, upset, unhappy, angry, irritated) |
| frustrated(adjective, upset, unhappy, angry, irritated) |
| fussbudgety(demanding, meticulous, fussy, exacting, finicky) |
| gaga(careless, unstable, unreasonable, unpredictable, changeable) |
| grim(tough, severe, firm, stern, problematic) |
| griping(adjective, upset, unhappy, angry, irritated) |
| grudging(adjective, upset, unhappy, angry, irritated) |
| grumbling(adjective, upset, unhappy, angry, irritated) |
| grumpy(adjective, upset, unhappy, angry, irritated) |
| hair-splitting |
| hard-to-please(adjective, particular) |
| helter-skelter(careless, unstable, unreasonable, unpredictable, changeable) |
| humorsome(careless, unstable, unreasonable, unpredictable, changeable) |
| hypercorrect(adjective, precise, thorough, meticulous) |