unannounced unbelievably unburden unceremoniously uncertain uncle uncolored uncomfortable uncomfortably unconvincingly uncover uncritical undependable undermine understated under undoubtedly undulation uneasiness uneven unexciting unexpectedly unfairly unfortunately unfortunate unguarded unhappily unhappy unimaginably unimpressed unlikely unmentionable unpleasantly unreasonably unremarkable unsettle unspeakable unspectacular unstable unsteady unstuck unsubtle unthinkingly until untoward unusually unusual unwanted unwavering unwilling unwished-for unwonted