final and irreversible
finish and completeness
firm and decisive
first and foremost
fitful and capricious
fitting and appropriate
fixity and finality
flaming and mendacious [mendacious = lying; untruthful]
flare and flicker
flatness and insipidity
flattery and toadyism
flexible and spontaneous
flickering and ambiguous
flighty and impetuous
flippant and contemptuous
florid and healthy [florid = ornate; flowery]
flotsam and jetsam
flow and fullness
flowery and figurative
fluctuating and transitory
fluency and flippancy
fluttering and restless
focus and concentrate
fogs and complications
foibles and follies
foiled and defeated
folly and indecorum
fools and underlings
force and effectiveness
formal and cold
formidable and profound
formlessness and exaggeration
fortitude and perseverance
foul and ominous
fragile and pale
fragments and morsels
fragrance and beauty
frailties and absurdities
frank and genial
free and independent
frequent and poignant
freshness and fragrance
fretful and timorous
friend and benefactor
frigid and pompous
frivolous and empty
froth and effervescence
frustrated and confounded
fuddled and contradictory
full and sonorous