Synonyms of informal in English:

informal


See definition of informal

adjective

1‘an informal discussion’

SYNONYMS
casual, relaxed, easy-going, natural, unceremonious, unofficial, non-formal, unstudied, unaffected
open, friendly, intimate
simple, unpretentious, easy
informal unstuffy, unbuttoned, chummy, pally, matey
ANTONYMS

formal, official

2‘an informal speech style’

SYNONYMS
colloquial, vernacular, idiomatic, demotic, non-standard, popular, dialectal, non-literary
simple, natural, familiar, everyday, unofficial, unpretentious
informal slangy, chatty, folksy
ANTONYMS

formal, literary

3‘the guys wore very informal clothes’

SYNONYMS
casual, relaxed, comfortable, everyday, sloppy, leisure
sportif
informal comfy, laid-back, sporty
ANTONYMS

formal, smart

4‘an informal job sector has developed’

SYNONYMS
unofficial, irregular, grey, black, back-door, illegal, illicit