| ad-lib(willing, spontaneous, unforced) |
| automatic(willing, spontaneous, unforced) |
| break loose(expression, willing, spontaneous, unforced) |
| casual(willing, spontaneous, unforced) |
| down(willing, spontaneous, unforced) |
| extemporaneous(willing, spontaneous, unforced) |
| extempore(willing, spontaneous, unforced) |
| free(willing, spontaneous, unforced) |
| free spirited(expression, willing, spontaneous, unforced) |
| from the hip(expression, idiom, willing, spontaneous, unforced) |
| impetuous(willing, spontaneous, unforced) |
| impromptu(willing, spontaneous, unforced) |
| improvised(willing, spontaneous, unforced) |
| impulsive(willing, spontaneous, unforced) |
| inevitable(willing, spontaneous, unforced) |
| instinctive(willing, spontaneous, unforced) |
| involuntary(willing, spontaneous, unforced) |
| irresistible(willing, spontaneous, unforced) |
| natural(willing, spontaneous, unforced) |
| off-the-cuff(willing, spontaneous, unforced) |