Definition of "demure"

Nan was very much delighted in her demure way, and that delight showed itself in her face and in her clear bright eyes.

1881, William Black, The Beautiful Wretch

I was coming back from the ladies' room when I saw her. She looked demure. Oval wire-rimmed glasses. A sky blue jacket buttoned over a long black-and-white flowered shirt.

2005, Maureen Dowd, Are Men Necessary?, page 311

[H]owever hard she pushed the tough-talkin' shtick, she remained doe-eyed, glowing and somehow unassailably demure.

2014 January 21, Hermione Hoby, “Julia Roberts interview for August: Osage County – 'I might actually go to hell for this …'”, in The Daily Telegraph‎

And in their daily lives, girls and women are pushed to conform to fairly narrow templates of behavior as demure or delicate.

2021 June 30, Motoko Rich, Hikari Hida, “Expected to Be Demure, Japan’s Girls Face Steep Hurdles to Athletic Dreams”, in The New York Times‎

Miss Lizzy, I have no doubt, would be as demure and coquettish, as if ten winters more had gone over her head.

c. 1824, Mary Russell Mitford, Walks in the Country

Your Wife Octavia, with her modeſt eyes, / […] ſhall acquire no Honour / Demuring vpon me:

c. 1606–1607, William Shakespeare, “The Tragedie of Anthonie and Cleopatra”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene xvi], page 363, column 2, line 30