WordWeb Online

1. Exhibiting restrained good taste
   "the room is pleasant and unpretentious";
   - understated, unostentatious
    
2. Lacking pretension or affectation
   "an unpretentious country church"; "her quiet unpretentious demeanour"
    
3. Not ostentatious
   "his unpretentious office";
   - unostentatious, unpretending

See also: honest, modest, plain, quiet, restrained, tasteful, tasty [US, informal], unpompous

Antonym: pretentious