unperceived (adj.) unpenetrable (adj.) unpaved (adj.) unpatriotic (adj.) unpardonable (adj.) unparalleled (adj.) unpalatable (adj.) unpaid (adj.) unpack (v.) unowned (adj.) unostentatious (adj.) unorthodoxy (n.) unorthodox (adj.) unoriginal (adj.) unorganized (adj.) unopposed (adj.) unofficial (adj.) unoffending (adj.) unoccupied (adj.) unobtrusive (adj.)