Synonyms and related words :
ad hoc, ad libitum, ad-lib, band-aid, caught napping, caught off balance, caught short, extemporaneous, extemporary, extempore, extemporized, haphazard, hasty, impromptu, improvisational, improvisatorial, improvise, improviso, jury-rigged, makeshift, makeshifty, off-the-cuff, offhand, precipitate, provisional, rough-and-ready, snap, stopgap, surprised, taken aback, taken by surprise, taken unawares, temporary, tentative, tripped up, unarranged, unbegun, unconcocted, uncontrived, undeliberated, undevised, unhatched, unmade, unmanufactured, unorganized, unplanned, unpremeditated, unprepared, unprimed, unready, unrehearsed, unstudied