| CLIFTIEST | • CLIFTY adj. broken into cliffs. |
| FAULTIEST | • faultiest adj. Superlative form of faulty: most faulty. • FAULTY adj. imperfect. |
| FEATLIEST | • featliest adj. Superlative form of featly: most featly. • FEATLY adj. (Shakespeare) graceful. |
| FERTILEST | • fertilest adj. Superlative form of fertile: most fertile. • FERTILE adj. productive. |
| FETTLINGS | • fettlings n. Plural of fettling. • FETTLING n. loose material thrown on the hearth of a furnace to protect it. |
| FILTHIEST | • filthiest adj. Superlative form of filthy: most filthy. • FILTHY adj. offensively dirty. |
| FILTRATES | • filtrates v. Third-person singular simple present indicative form of filtrate. • FILTRATE v. to filter. |
| FISTULATE | • fistulate v. (Obsolete, transitive, intransitive) To make or become hollow like a fistula, or pipe. • fistulate adj. Hollowed like a fistula. • FISTULATE adj. hollow and cylindrical, like a pipe or reed, also FISTULAR, FISTULOSE, FISTULOUS. |
| FLINTIEST | • flintiest adj. Superlative form of flinty: most flinty. • FLINTY adj. resembling flint. |
| FLIRTIEST | • flirtiest adj. Superlative form of flirty: most flirty. • FLIRTY adj. lightheartedly amorous, also FLIRTISH. |
| FLITTERNS | • flitterns n. Plural of flittern. • FLITTERN n. bark obtained from young oak trees. |
| FLOATIEST | • floatiest adj. Superlative form of floaty: most floaty. • FLOATY adj. tending to float. |
| FRUITLETS | • fruitlets n. Plural of fruitlet. • FRUITLET n. a small fruit. |
| LIFTGATES | • liftgates n. Plural of liftgate. • LIFTGATE n. a rear panel on a station wagon that opens upward. |
| SWIFTLETS | • swiftlets n. Plural of swiftlet. • SWIFTLET n. a cave-dwelling swift (bird). |