| hundred-to-one(doubtful, unlikely, implausible) |
| iffy(doubtful, unlikely, implausible) |
| inconceivable(adjective, light, obscure, thin, strange) |
| isolated(light, thin, rare, reclusive, uncompanionable) |
| not expected(expression, doubtful, unlikely, implausible) |
| not likely(expression, adjective, doubtful, unlikely, implausible) |
| odd(extraordinary, unusual, exceptional, special, rare) |
| off the beaten track(expression, adjective, extraordinary, unusual, exceptional) |
| outside chance(expression, adjective, doubtful, unlikely, implausible) |
| questionable(doubtful, unlikely, implausible) |
| remarkable(light, thin, extraordinary, unusual, exceptional) |
| scarce(light, thin, unusual, special, rare) |
| seldom(light, thin, unusual, special, rare) |
| semioccasional |
| singular(light, thin, extraordinary, unusual, strange) |
| slim(doubtful, unlikely, implausible) |
| slim and none(expression, idiom, doubtful, unlikely, implausible) |
| sporadic(light, thin, unusual, special, rare) |
| subtile |
| subtle |