Letter U

ubiquitous - omnipresent, pervasive
ulterior - hidden, covert
ultimatum - demand
ululate - howl, wail
umbrage - resentment
unabashed - shameless, brazen
unabated - ceaseless
unaffected - natural, sincere
unanimity - agreement
unassuming - modest
unavailing - useless, futile
unawares - suddenly, unexpectedly
unbecoming - unfitting
unbridled - unrestrained
uncanny - mysterious, inexplicable
unconscionable - unscrupulous
uncouth - uncultured, crude
unctuous - insincere
undermine - weaken
underpin - support
underscore - emphasize
understudy - a stand-in
underworld - criminal world
underwrite - agree to finance, guarantee
undue - unjust, excessive
undulate - surge, fluctuate
unduly - excessive
unequivocal - unambiguous,categorical
unexceptionable - beyond criticism
unfailing - steadfast, unfaltering
unfathomable - puzzling, incomprehensible
unflagging - untiring, unrelenting
unflappable - not easily upset
unfrock - discharge
unfurl - open up, spread out
ungainly - awkward
uniformity - sameness
unilateral - action taken by only one party
unimpeachable - exemplary
unison - together
unkempt - disheveled
unmitigated - complete, harsh
unmoved - firm, steadfast
unprecedented - without previous occurrence
unremitting - relentless
unsavory - distasteful, offensive
unscathed - unhurt
unseat - displace
unseemly - unbecoming, improper
unstinting - generous
unsullied - spotless, pure
unsung - neglected, not receiving just recognition
untenable - cannot be achieved
untoward - perverse, unseemly
unwarranted - unjustified
unwieldy - awkward
unwitting - unintentional
upshot - result
urbane - refined, worldly
ursine - bear-like
usurp - seize, to appropriate
usury - lending money at high rates
utilitarian - pragmatic, useful
utopia - paradise
utter - complete
uxorious - a doting husband