ferment,substance/become excited
ferocity,savage cruelty
ferret,discover by searching/search
fertile,producing much/full of ideas
fertilize,make fertile or productive
fervid,intense/zealous 
fervid,showing earnest feeling
fervor,warmth of feelings/earnestness
fervor,a glowing ardor
fetter,to shackle/put in chains 
feud,bitter quarrel over a long period of time
fidelity,loyalty/accuracy
fidget,move restlessly/make nervous
figurehead,carved image on the prow of a ship
finesse,delicate way of dealing with a situation
finical,too fussy about food, clothing
finicky,finical
finite,limited/having bounds
fission,splitting or division (of cells)
fixate,stare at
flagrant,conspicuously wicked
flamboyant,brightly colored/florid
flammable,having tendency to burst into flames
flaunting,show off complacently
flaw,crack/lessen value
flax,pale yellow (hair)/a plant
fledged,able to fly/trained/experienced
fleet,number of ships/quick-moving
fleeting,passing quaickly
flexibility,easily bent without braking
flinch,drow/move back/wince
florid,very much ornamented/naturally red (of face)
floridness,ruddiness/heavily decorated/ornateness 
flout,reject/mock/to go against (as in going against tradition or conventions) 
fluster,make nervous or confused
foible,defect of character (a person is wrongly proud)
foil,prevent from carrying out/contrast
foment,put smth warm (to lessen the pain)
foppish,like a man who pays too much attention to his clothes
forbear,refrain from/be patient/ancestor
forbearance,patience/willingness to wait
ford,shallow place in a river (to cross)
forestall,prevent by taking action in advance/preempt 
forfeit,suffer the loss of smth
forge,workshop for the shaping of metal/to shape metal/lead
forgery,counterfeit
forswear,renounce/disallow/repudiate 
fortify,strengthen
fortuitous,happening by chance
foster,nurture/care for