523. facilitation
524. fait accompli 
525. familial* - Of or pertaining to family. 
526. fashionmonger
527. fastidious
528. fathomless
529. Faulknerian
530. faultfinding
531. featherweight
532. febricity
533. femininity
534. ferine
535. fetlock*
536. fiancé (male)*
537. Fibonacci sequence
538. ficus, Ficus
539. figurehead
540. filched
541. filial
542. fishmonger*
543. fissionable
544. fissiped
545. flagelliform*
546. flamenco*
547. flange
548. fleeciness
549. flout
550. fluoroscope
551. foliicolous
552. foray
553. forceps* - An instrument used in surgery or medical procedures for grasping and holding objects, similar to tongs or pincers.
554. forethought
555. forgettable
556. Formica (trademark)
557. forswear, foreswear
558. fourragère
559. franchisee
560. Fräulein, fräulein
561. frenetic, phrenetic
562. frugivorous
563. fruition
564. fugacious* - Fleeting, fading quickly, transient. 
565. fugleman
566. funambulist
567. fungistat
568. futurity race* - a race that competitors enter in advance