formal

adj. ceremonious; conventional; according to custom; stiff; strict; symmetrical; requiring fancy dress

n. occasion which requires fancy dress (dance, ball, etc.); evening gown

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Adjective
1. being in accord with established forms and conventions and requirements (as e.g. of formal dress); "pay one's formal respects"; "formal dress"; "a formal ball"; "the requirement was only formal and often ignored"; "a formal education"
(antonym) informal
(similar) ceremonial
(see-also) conventional
(attribute) formality, formalness
2. characteristic of or befitting a person in authority; "formal duties"; "an official banquet"
(similar) official
3. (of spoken and written language) adhering to traditional standards of correctness and without casual, contracted, and colloquial forms; "the paper was written in formal English"
(antonym) informal
(similar) literary
(attribute) formality, formalness
4. represented in simplified or symbolic form
(synonym) conventional, schematic
(similar) nonrepresentational
(classification) fine arts, beaux arts
5. logically deductive; "formal proof"
(similar) logical
6. refined or imposing in manner or appearance; befitting a royal court; "a courtly gentleman"
(synonym) courtly, elegant, stately
(similar) dignified

adj. formal, conventional, according to custom, strict

adj. formal; serious, earnest; dependable; reputable; staid; sound