| aleatory(adjective, spontaneous, haphazard, accidental, unintended) |
| accidental(adjective, unplanned, unintended, inadvertent) |
| adventitious(adjective, accidental, unintended) |
| aimless(unplanned, accidental, inadvertent) |
| casual(unplanned, accidental, inadvertent) |
| chance(unplanned, accidental, inadvertent) |
| erratic(unplanned, accidental, inadvertent) |
| extemporaneous(unplanned, accidental, inadvertent) |
| forced |
| fortuitous(adjective, unplanned, accidental, unintended, inadvertent) |
| haphazard(adjective, unplanned, accidental, unintended, inadvertent) |
| impromptu(adjective, accidental, unintended) |
| inadvertent(unplanned, accidental, unintended) |
| involuntary(unplanned, accidental, inadvertent) |
| purposeless(unplanned, accidental, inadvertent) |
| random(adjective, unplanned, accidental, unintended, inadvertent) |
| spontaneous(adjective, accidental, unintended) |
| unconscious(unplanned, accidental, inadvertent) |
| undesigned(adjective, unplanned, accidental, unintended, inadvertent) |
| undevised(unplanned, accidental, inadvertent) |