| easier said than done(expression, idiom, tough, severe, painful) |
| effortful(tough, severe, difficult, awkward, painful) |
| entangled(adjective, hard, fancy, difficult, complex) |
| exacting(tough, severe, painful, trying) |
| fancy(adjective, hard, difficult, complex, intricate) |
| far-fetched(uncertain, doubtful, shaky, unsure, unlikely) |
| farfetched(unreasonable, dubious, suspect, shady, unlikely) |
| fat chance(expression, shaky, unlikely, unpromising) |
| fluctuant(adjective, uncertain, nervous, doubtful, shaky) |
| fly-by-night(adjective, uncertain, nervous, doubtful, hesitant) |
| fuzzy(vague, unclear, ambiguous, misleading, indistinct) |
| galling(tough, severe, painful, trying) |
| gargantuan(tough, severe, painful, trying) |
| gasser(adjective, hard, fancy, difficult, complex) |
| gnarled |
| gnarly |
| hanging by a thread(expression, adjective, idiom, delicate, uncertain) |
| hard-won(tough, severe, painful, trying) |
| hard of belief(expression, idiom) |
| hard to believe(expression, idiom) |