| individual(unusual, strange, unique, eccentric, atypical) |
| informal(unusual, strange, unique, eccentric, atypical) |
| insane(adjective, simple, silly, foolish, crazy) |
| invalid(irrational, arbitrary, perverse, unreasoned, unscientific) |
| irrational(adjective, wrong, false, unusual, strange) |
| irregular(extraordinary, unusual, wild, strange, crazy) |
| just plain nuts(expression, idiom) |
| loopy |
| lunatic(adjective, simple, silly, foolish, crazy) |
| mad(adjective, simple, unusual, strange, silly) |
| nonsensical(strange, silly, foolish, stupid, senseless) |
| off |
| off-center(adjective, extraordinary, unusual, wild, strange) |
| off the beaten track(expression, idiom, unusual, strange, unique) |
| off the hinges(expression, idiom) |
| off the track(expression, idiom) |
| offbeat(unusual, wild, strange, crazy, fantastic) |
| out |
| out in left field(expression, adjective, idiom, unusual, strange) |
| out of the ordinary(expression, idiom, unusual, strange, unique) |