uninteresting, lifeless, obscure, and commonplace
unity, aggressiveness, efficiency, and force
unkind, severe, oppressive, and callous
unpractical, childish, slipshod, and silly
unreasonable, foolish, excessive, and absurd
unrivaled, unequaled, incomparable, and matchless
upright, high-minded, brave, and liberal
urgent, important, immediate, and imperative
usage, custom, habit, and practise