(adv.) Extemporaneously.

a beneplacito a discretion ad arbitrium ad libitum ad-libbing al piacere arrangement at choice at pleasure at short notice at sight at will be caught napping be surprised be taken unawares be unprepared by ear caught napping caught off balance caught short cook up dash off disqualification do offhand extemporaneous extemporaneously extemporaneousness extemporarily extemporariness extemporary extempore extemporization extemporize extemporized fake go off half-cocked haphazard hasty have no plan impromptu improvisate improvisation improvisatorial improvise improvised improvision improviso incapability incompetence jury-rig jury-rigged knock off lack of preparation lash up make up makeshift measure nonpreparation nonpreparedness off the cuff off the hip off-the-cuff offhand on sight out of hand planlessness play by ear playing by ear precipitate pro tempore rough-and-ready scrap the plan snap stopgap strike off surprised taken aback taken by surprise taken unawares temporary arrangement temporary measure throw off throw together toss off toss out tripped up unarranged unbegun unconcocted uncontrived undeliberated undevised unfitness unfittedness unforced unhatched unmade unmanufactured unorganized unplanned unpremeditated unprepared unpreparedness unprimed unqualification unqualifiedness unreadiness unready unrehearsed unstudied unsuitability unsuitableness unsuitedness vamp vulnerability whip up whomp up wing it without coercion