Unconscionable
Not controlled by conscience; unscrupulous
Ubiquitous
Being everywhere at the same time
Unctuous
Oily; insincere
Unremitting
Unceasing; unabated; relentless
Unwitting
Unintentional; ignorant; not aware
Usurp
To seize wrongfully
Utilitarian
Stressing usefulness or utility above all other qualities; pragmatic