Synonyms of informal

informal

adjective

(ˌ)in-ˈfȯr-məl 

1

as in unconventional

not rigidly following established form, custom, or rules

an informal meeting allowed everyone to get acquainted

Synonyms & Similar Words

• unconventional
• unofficial
• unorthodox
• irregular
• casual
• unceremonious
• heterodox
• unauthorized
• relaxed
• easygoing
• familiar
• offhand
• free and easy
• lax
• ultracasual
• loose

Antonyms & Near Antonyms

• formal
• regular
• conventional
• routine
• ceremonial
• orthodox
• proper
• correct
• ceremonious
• rigid
• decorous
• stiff
• restrained
• stuffy
• inhibited
• constrained
• uptight

2

as in casual

not designed to be worn only on special occasions

chose an informal flowery dress

Synonyms & Similar Words

• casual
• everyday
• relaxed
• workaday
• sporty
• slovenly
• sloppy
• dégagé
• shabby
• unkempt
• dressed down

Antonyms & Near Antonyms

• formal
• best
• dressy
• Sunday
• elegant
• fashionable
• stylish
• noncasual
• chic
• smart
• neat
• tidy
• trim
• dressed up
• semiformal

3

as in colloquial

used in or suitable for speech and not formal writing

the use of informal language in a scholarly article is really inappropriate

Synonyms & Similar Words

• colloquial
• vernacular
• nonformal
• conversational
• vulgar
• nonliterary
• dialectical
• unliterary
• dialectal
• slang
• unbookish
• regional
• nonstandard
• incorrect
• uneducated
• ungrammatical
• substandard
• slangy
• unlearned
• nongrammatical

Antonyms & Near Antonyms

• formal
• literary
• learned
• standard
• bookish
• proper
• correct
• grammatical
• educated
• genteel
• undialectical

Example Sentences

Recent Examples of informal

The same is true of the price of pesticide, which is brought into Gaza via informal channels and sold by traders at a steep markup. — Ghada Abdulfattah, Christian Science Monitor, 2 Oct. 2026

Gun homicides mostly affect South Africa’s poorest communities in townships and informal settlements made up of shacks and small homes on the edges of big cities. — Gerald Imray, Los Angeles Times, 27 Sep. 2026

Gun homicides mostly affect South Africa's poorest communities in townships and informal settlements made up of shacks and small homes on the edges of many big cities. — ABC News, 27 Sep. 2026

In addition to her art practice, Endaya is also a writer, curator, organizer, and informal educator. — Francesca Aton, ARTnews.com, 25 Sep. 2026