| featherweight(adjective, light, slight, easy, thin) |
| feathery(adjective, light, slight, easy, thin) |
| fermenting(adjective, foaming, fizzing) |
| festive(adjective, bright, happy, energetic, active) |
| feverish(adjective, excited) |
| fickle(careless, lively, unstable, unreasonable, unreliable) |
| filmy(adjective, light, slight, easy, thin) |
| fired |
| fitful(careless, unstable, unreasonable, unpredictable, changeable) |
| fizz |
| fizzling |
| flaky(careless, lively, unstable, unreasonable, unpredictable) |
| flat |
| flimsy(adjective, light, slight, easy, thin) |
| flip(lively, unpredictable, changeable, aggressive, arrogant) |
| floatable(adjective, light, slight, easy, thin) |
| floating(adjective, light, slight, easy, thin) |
| fluffy(adjective, light, slight, easy, thin) |
| freakish(careless, unstable, unreasonable, unpredictable, changeable) |
| friable(adjective, light, slight, easy, thin) |