INFORMAL
informal
(adjective) not formal; “conservative people unaccustomed to informal dress”; “an informal free-and-easy manner”; “an informal gathering of friends”
informal
(adjective) used of spoken and written language
cozy, intimate, informal
(adjective) having or fostering a warm or friendly and informal atmosphere; “had a cozy chat”; “a relaxed informal manner”; “an intimate cocktail lounge”; “the small room was cozy and intimate”
informal, loose
(adjective) not officially recognized or controlled; “an informal agreement”; “a loose organization of the local farmers”
Source: WordNet® 3.1
Etymology
Adjective
informal (comparative more informal, superlative most informal)
Not formal or ceremonious.
Not in accord with the usual regulations.
Suited for everyday use.
(of language) Reflecting everyday, non-ceremonious usage.
(gardening) Not organized; not structured or planned.
Synonyms
• (not formal or ceremonious): casual
• (not in accord with the usual regulations): unofficial
• (suited for everyday use): casual
• (language: reflecting everyday, non-ceremonious usage): colloquial
Antonyms
• formal
Anagrams
• formalin
Source: Wiktionary
In*form"al, a. Etym: [Pref. in- not + formal.]
1. Not in the regular, usual, or established form; not according to
official, conventional, prescribed, or customary forms or rules;
irregular; hence, without ceremony; as, an informal writting,
proceeding, or visit.
2. Deranged in mind; out of one's senses. [Obs.]
These poor informal women. Shak.
Source: Webster’s Unabridged Dictionary 1913 Edition