Demure is an adjective which means a modest, shy or reserved manner.
Synonyms of Demure: bashful, reserved, sedate, shy, quiet.
Antonyms of Demure: brazen, pretentious, immodest, impudent, shameless.
Note: Do not confuse the demure with demur, which is a verb meaning to object or take exception.
1. Brazen Durga became surprisingly demure when her husband walked into the room.
2. It must be nice to have such a demure child; my sister is so loud and unruly.
3. People with demure natures often cannot mingle with others.