ad-lib aimless caught napping caught off balance caught short designless desultory extemporaneous extemporized haphazard hasty hit-or-miss impromptu improvised inadvertent indiscriminate involuntary makeshift precipitate purposeless rough-and-ready snap surprised taken aback taken by surprise taken unawares tripped up unarranged unbegun unconcocted unconscious unconsidered uncontrived undeliberated undesigned undevised unguarded unguided unhatched unintended unintentional unmade unmanufactured unmeant unmeditated unorganized unpremeditated unprepared unprimed unprompted unpurposed unready unstudied unthinking unthought unthought-of unwitting