| fiction |
| figment of the imagination(noun, fiction) |
| flash(noun, feeling, drive, passion, desire) |
| fleetingness(noun, caprice) |
| flippancy(noun, play, happiness, fun, humor) |
| flirting(merriment, triviality, levity, silliness, playfulness) |
| fluctuation(noun, caprice) |
| flummery(ornament, merriment, triviality, levity, silliness) |
| folly(noun, trifling, merriment, triviality, whim) |
| freakiness |
| freakish inspiration |
| freakishness |
| fribble(merriment, triviality, levity, silliness, playfulness) |
| frippery(merriment, triviality, levity, silliness, playfulness) |
| frivolousness(merriment, triviality, levity, silliness, playfulness) |
| funniness(noun, happiness, fun, humor, wit) |
| furor(noun, passion, fashion, fantasy, craze) |
| gag(noun, fancy, trick, fun, humor) |
| gaiety(noun, play, happiness, fun, humor) |
| game(noun, art, craft, sport, fun) |