| extemporaneous(adjective, free, casual, impulsive, impulse) |
| extempore(adjective, free, casual, impulsive, unprepared) |
| impromptu(adjective, free, casual, impulsive, unprepared) |
| by ear(expression, adjective, free, fake, informal) |
| improv(adjective, free, fake, informal, casual) |
| improvisational |
| improvisatorial |
| improvised(adjective, free, casual, impulsive, impulse) |
| improviso(adjective, free, fake, informal, casual) |
| off-the-cuff(adjective, spontaneous, unprepared, impromptu, unrehearsed) |
| on-the-spot(adjective, free, fake, informal, casual) |
| on impulse(expression, adjective, free, fake, informal) |
| spontaneous(adjective, free, informal, casual, impulse) |
| ad-lib(adjective, free, fake, casual, impulsive) |
| ad hoc(expression, adjective, free, casual, unrehearsed) |
| ad lib(expression, adjective, free, informal, casual) |
| at first glance(expression, idiom, free, informal, casual) |
| automatic(adjective, free, informal, casual, impulsive) |
| autoschediastic(adjective, free, fake, casual, impulsive) |
| casual(adjective, free, informal, impulsive, unprepared) |