ultimately.adverb
in the end; finally; eventually
ultimate.adjective
being last in a series, process, or progression; fundamental; elemental (an ultimate truth); of the greatest significance; maximum (Nirvana is a human being's highest goal)

unrelenting.adjective
not softening or yielding in determination; hard; stern (an unrelenting leader; the principal was too stern with the students); not letting up or weakening in vigor or pace; constant (the unrelenting struggle) 
unrelentingly.adverb

usurp.verbs
intransitive senses-to seize or exercise authority or possession wrongfully; to act as your own authority 
transitive senses-to seize and hold (as office, place, or powers) in possession by force or without right (usurp a throne); to take or make use of without right (usurped the rights to his life story); to take the place of by or as if by force; supplant (must not let stock responses based on inherited prejudice usurp careful judgment) 
usurper, usurpation.nouns

utmost.noun
the most possible; the extreme limit; the highest attainable point or degree (the utmost in reliability); the highest, greatest, or best of one's abilities, powers, and resources (will do our utmost to help) 
as an.adjective-situated at the farthest or most distant point; extreme (the utmost point of the earth); of the greatest or highest degree, quantity, number, or amount (a matter of utmost concern) 

unobtrusive.adjective
not obtrusive not blatant, arresting, or aggressive; inconspicuous
unobtrusiveness.noun
unobtrusively.adverb

untoward.adjective
hard to deal with; stubborn; unruly; unseemly 

unravel, unraveled, unraveling, unravels.verbs
transitive use.to make clear of confusion or involvement; to undo or ravel (yeah, they mean the same thing) the knitted fabric of; to separate (entangled threads); to separate and clarify the elements of (something mysterious or baffling); solve
intransitive use to become unraveled

unfetter.transitive verb
free from restraint of any kind; liberate (see fetter)

usury.noun
inflected form(s).plural.usuries
interest on money; the lending of money with an interest charge for its use

underling.noun
one who is under the orders of another; subordinate; inferior

untenable.adjective
not tenable; that cannot be defended; incapable of being tenanted or occupied; being such that maintenance or defense is impossible (an untenable document); being such that occupation or habitation is impossible (untenable quarters {the place being so messy, no one would live there})
untenability, untenableness.nouns
untenably.adverb

utilize, utilizing, utilized.transitive verbs
to put to use; get profit or benefit from by using
utilization.noun
utilizable.adjective

uracil.noun
a pyrimidine-(colorless, crystalline organic-compound)-derivative, which is a major component of nucleic acids and nucleotides. Like purine is an organic nitrogenous base soluble in water

ultrasonic.adjective
having a frequency above the human ear's audibility limit of about 20,000 hertz – used of waves and vibrations 
ultrasonically.adverb

universe.noun
the whole body of things and phenomena observed or postulated; cosmos; the entire celestial cosmos; our home universe being the Milky Way-Galaxy

unified field theory.noun
is intended to describe nature at all energies; i.e. what happens if the energies can be adjusted to equivalent GeV, say 10 to the 16th or 18th power? 

Einstein spent 30 years of his life searching for a unifying theory to reconcile that which he was aware of regarding the functioning of the Universe. He never found it. Dr. John Hagelin has. 

Life on Earth is very sensitive to the values of fundamental-physical constants. The tiniest change in any of these.(or these).would result in changes so drastic that life as we know it would not, could not, exist. It's the Universal Intelligent Energy that continues sustaining the universe and our world as we know it.

unique.adjective
one and only; different from all others; having no like or equal; unusual; rare 

unmitigated.adjective
not lessened or eased 

utter, uttered, uttering, utters.transitive verbs
to send forth with the voice; to articulate (words); pronounce or speak
utterable.adjective
utterer.noun
utter.adjective
complete; absolute; entire (utter nonsense); utter darkness

utterly.adverb
entirely, completely, absolutely

unbiased.adjective
without bias or prejudice; impartial; fair
unbiasedly.adverb
unbiasedness.noun

unqualified.adjective
not modified by conditions or reservations; absolute.(an unqualified refusal); lacking the proper or required qualifications (unqualified for the job)
unqualifiedly.adverb

unfounded.adjective
not based on fact or sound evidence; groundless; baseless; not yet established
unfoundedly.adverb
unfoundedness.noun

undermine, undermined, undermining, undermines.transitive verbs
to weaken by wearing away a base or foundation (water has undermined the stone foundations); to weaken, injure, or impair, often by degrees or imperceptibly; sap (ate hours can undermine one's health); to dig a mine or tunnel beneath

unerring.adjective
committing no mistakes; consistently accurate
unerringly.adverb