| incidental |
| accidental(adjective, casual, useless, extra, worthless) |
| negligible(adjective, small, insignificant, unimportant, trivial) |
| peripheral(adjective, extra, minor, petty, unnecessary) |
| petty(adjective, small, insignificant, unimportant, trivial) |
| surplus(adjective, extraordinary, new, spare, fresh) |
| uncalled-for(adjective, spare, extreme, useless, extra) |
| additional(adjective, extraordinary, new, spare, fresh) |
| casual(adjective, small, insignificant, unimportant, trivial) |
| fortuitous(adjective, casual, useless, extra, worthless) |
| gratuitous(adjective, spare, extreme, useless, extra) |
| inconsequential(adjective, insignificant, unimportant, trivial, irrelevant) |
| inconsiderable(adjective, small, insignificant, unimportant, trivial) |
| inferior(adjective, small, insignificant, unimportant, trivial) |
| irrelevant(adjective, insignificant, unimportant, trivial, minor) |
| supererogatory(adjective, spare, extreme, extra, unwarranted) |
| useless(adjective, spare, insignificant, extreme, casual) |
| worthless(adjective, insignificant, casual, unimportant, useless) |
| adventitious |
| dinky |