faint, feint, and feign all come from the French, feindre, which is derived from the Latin, fingo, shape. The first two, similarly pronounced, have very different significations. Faint means a sudden loss of consciousness or swoon; feint signifies a deceptive move or pretense. To feign is to make a false show of; pretend.
fake: Slang term for imposition; fraud; also, fictitious or manufactured news. Expressive but inelegant.
fakement: Slang for an act of fraud. Less desirable than preceding and equally inelegant.
fanatic. Compare enthusiast.
farewell: When separated by a pronoun farewell is written as two words; as, fare you well. Exception has been taken to Byron's pathetic lines
Fare thee well, and if for ever,
Then for ever, fare thee well;
but this is hypercriticism for here the pronoun is nothing but the Anglo-Saxon dative.
farther, further: Farther should be used to designate longitudinal distance; further to signify quantity or degree. Thus, "How much farther have we to go?" "Proceed no further along that course."