ad-lib caught napping caught off balance caught short extemporaneous extemporized haphazard hasty impromptu improvised makeshift precipitate rough-and-ready snap surprised taken aback taken by surprise taken unawares tripped up unarranged unbegotten unbegun unborn unconceived unconcocted uncontrived uncreated undeliberated undevised unhatched unmanufactured unorganized unplanned unpremeditated unprepared unprimed unproduced unready unstudied