WordWeb Online

1. Not conforming to accepted rules or standards
   "her unconventional dress and hair style"
    
2. Not conventional or conformist
   "unconventional life styles"
    
3. Not conforming to legality, moral law, or social convention
   "an unconventional marriage";
   - improper, unlawful

See also: alternative, bizarre, bohemian, convention, conventionalism, conventionality, devil-may-care, eccentric, far-out, flakey, flaky, freakish, freaky, funky, go-as-you-please, gonzo [N. Amer], irregular, kinky, maverick, offbeat, off-the-wall, original, outlandish, outré, quirky, raffish, rakish, spaced-out, spacey, spacy, unorthodox, way-out

Antonym: conventional

Encyclopedia: Unconventional