Informality is the quality of being relaxed, casual, and free from strict rules or formal requirements. When a birthday party has an air of informality, guests might wear jeans instead of fancy clothes, sit wherever they like, and help themselves to food without waiting for an official announcement.

The word describes situations where people interact naturally without worrying about elaborate etiquette or rigid procedures. A classroom discussion has informality when students raise points freely rather than raising hands and waiting to be called on. A business meeting conducted with informality might start with friendly conversation and allow people to interrupt with questions rather than following a strict agenda.

Informality often makes people feel more comfortable and relaxed. When you visit a friend's house and their parents say “make yourself at home,” they're encouraging informality: you can grab a snack from the kitchen or flop on the couch without asking permission each time.

The opposite is formality, where specific rules govern behavior. A state dinner at the White House has formality; a backyard barbecue has informality. Neither is better: different situations call for different approaches. Understanding when informality fits and when formality is needed shows social awareness. The key is matching your behavior to what the situation requires.