Demure means quiet, modest and reserved. A demure smile, demure in company, a demure dress.
It is used almost only of women and carries an old expectation with it, which is why it can sound like a compliment and a cage at once. Of clothing it simply means modest in cut.
1adjectivedemureQuiet, modest and reserved.
“The quiet, demure girl in the corner turned out to be the best singer in the class.”
demure is a quality.
Middle English demure comes from an Anglo-Norman phrase meaning of mature bearing.
Proto-Indo-European
*meh₂-
Anglo-Norman
de mure port — with a mature demeanor
Middle English
demure
English, today
demure
Middle English demure, demwre, an abbreviation of Anglo-Norman de mure port (“with a mature demeanor”) (compare Old French meur from Latin mātūrus):
Etymology from Wiktionary, CC BY-SA