improvisational

made or done without previous thought or preparation an improvisational comedy sketch that showcased his lightning-fast wit Synonyms ad hoc, ad-lib, down and dirty, extemporary, extempore, impromptu, extemporaneous, improvised, offhand, offhanded, off-the-cuff, snap, spur-of-the-moment, unconsidered, unplanned, unpremeditated, unprepared, unrehearsed, unstudiedRelated Words unscripted; automatic, impulsive, instinctive, involuntary, spontaneous; casual, cursive, informal, unauthorized; half-baked, half-cocked, ill-advisedNear Antonyms deliberate, intended, intentionalAntonyms considered, planned, premeditated, premeditative, prepared, rehearsed