Meaning of INFORMAL in English

INFORMAL

adj.1 without ceremony or formality (just an informal chat).

2 (of language, clothing, etc.) everyday; normal.

Phrases and idioms:

informal vote NZ & Austral. an invalid vote or voting paper.

Derivatives:

informality n. (pl. -ies). informally adv.

Oxford English vocab.      Оксфордский английский словарь.