WordWeb Online

1. Not formal
   "conservative people unaccustomed to informal dress"; "an informal free-and-easy manner"; "an informal gathering of friends"
    
2. Used of spoken and written language
    
3. Not officially recognized or controlled
   "an informal agreement";
   - loose
    
4. Having or fostering a warm or friendly and informal atmosphere
   "a relaxed informal manner";
   - cozy [N. Amer], intimate, cosy [Brit, Cdn]

See also: casual, colloquial, common, conversational, daily, epistolary, epistolatory, everyday, folksy, formality, formalness, free-and-easy, friendly, nonliterary, slangy, subliterary, unceremonial, unceremonious, unliterary, unofficial, unrhetorical, vernacular, vulgar

Antonym: formal

Encyclopedia: Informal