Exemption, immunity, liberty, license, privilege.
Explicit, express.
Faint, faint-hearted, faltering, half-hearted, irresolute, languid, listless, purposeless.
Faithful, loyal, stanch, trustworthy, trusty.
Fanciful, fantastic, grotesque, imaginative, visionary.
Folly, imbecility, senselessness, stupidity.
Fling, gibe, jeer, mock, scoff, sneer, taunt.
Flock, bevy, brood, covey, drove, herd, litter, pack.
Fluctuate, hesitate, oscillate, vacillate, waver.