| Term | Definition |
| flippant | ADJ. lacking proper seriousness |
| flit | V. fly; dart lightly; pass swiftly by |
| floe | N. mass of floating ice |
| flora | N. plants of a region or era |
| florid | ADJ. ruddy; reddish; flowery |
| flotsam | N. drifting wreckage |
| flounder | V. struggle and thrash about; proceed clumsily or falter |
| flourish | V. grow well; prosper; make sweeping gestures |
| flout | V. reject; mock; show contempt for |
| fluctuate | V. waver; shift |
| fluency | N. smoothness of speech |
| fluke | N. unlikely occurrence; stroke of fortune |
| fluster | V. confuse |
| fluted | ADJ. having vertical parallel grooves (as in a pillar) |
| flux | N. flowing; series of changes |
| fodder | N. coarse food for cattle, horses, etc. |
| foible | N. weakness; slight fault |
| foil | N. contrast V. defeat; frustrate |
| foist | V. insert improperly; palm off |
| foliage | N. masses of leaves |
| foment | V. stir up; instigate |
| foolhardy | ADJ. rash |
| fop | N. dandy; man excessively preoccupied with his clothes |
| foray | N. raid |
| forbearance | N. patience |
| ford | N. place where a river can be crossed on foot. also V. |
| forebears | N. ancestors |
| foreboding | N. premonition of evil |
| forensic | ADJ. suitable to debate or courts of law |
| foreshadow | V. give an indication beforehand; portend; prefigure |
| foresight | N. ability to foresee future happenings; prudence |
| forestall | V. prevent by taking action in advance |
| forgo | V. give up; do without |
| forlorn | ADJ. sad and lonely; wretched |
| formality | N. ceremonious quality; something done just for form's sake |
| formidable | ADJ. inspiring fear or apprehension; difficult; awe-inspiring |
| forsake | V. desert; abandon; renounce |
| forswear | V. renounce; abandon |
| forte | N. strong point or special talent |
| forthright | ADJ. straightforward; direct; frank |
| fortitude | N bravery; courage |
| fortuitous | ADJ. accidental; by chance |
| foster | V. rear; encourage. also ADJ. |
| founder | V. fail completely; sink N. person who establishes (an organization, business) |
| fracas | N. brawl, melee |
| fractious | ADJ. unruly; disobedient; irritable |
| frail | ADJ. weak |
| franchise | N. right granted by authority; right to vote; license to sell a product in a particular territory |
| frantic | ADJ. wild |
| fraudulent | ADJ. cheating; deceitful |
| fraught | ADJ. filled or charged with; causing emotional distress |
| fray | N. brawl |
| frenetic | ADJ. frenzied; frantic |
| frenzied | ADJ. madly excited |
| fresco | N. painting on plaster (usually fresh) |
| fret | V. be annoyed or vexed |
| friction | N. clash in opinion; rubbing against |
| frieze | N. ornamental band on a wall |
| frigid | ADJ. intensely cold |
| fritter | V. waste |
| frivolous | ADJ. lacking in seriousness; self-indulgently carefree; relatively unimportant |
| frolicsome | ADJ. prankish; gay |
| frond | N. fern leaf; palm or banana leaf |
| froward | ADJ. stubbornly contrary; obstinately disobedient |
| fructify | V. bear fruit |
| frugality | N. thrift; economy |
| fruiton | N. bearing of fruit; fulfillment; realization |
| frustrate | V. thwart; defeat |
| fugitive | ADJ. fleeting or transitory; roving |
| fulcrum | N. support on which a lever rests |
| fulminate | V. denounce thunderously; explode |
| fulsome | ADJ. disgustingly excessive |
| functionary | N. official |
| fundamental | V. basic; primary; essential |
| funereal | ADJ. sad; solemn |
| furor | N. frenzy; great excitement |
| furtive | ADJ. stealthy; sneaky |
| fusillade | N. simultaneous firing or outburst (of missiles, questions, etc.) |
| fusion | N. union; blendering; synthesis |
| futile | ADJ. useless; hopeless; ineffectual |
| gadfly | N. animal-biting fly; an irritating person |
| gaffe | N. social blunder |