Adjective
1. not formal;
"conservative people unaccustomed to informal dress""an informal free-and-easy manner""an informal gathering of friends"2. not officially recognized or controlled;
"an informal agreement""a loose organization of the local farmers"3. used of spoken and written language
4. having or fostering a warm or friendly atmosphere; especially through smallness and informality;
"had a cozy chat""a relaxed informal manner""an intimate cocktail lounge""the small room was cozy and intimate"