Definition of "debonair"

Let be that Ladie debonaire, / Thou recreant knight, and soone thy selfe prepaire / To battell […] .

1590, Edmund Spenser, “Book II, Canto VI”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie

She was a New York City person. Sacco is nervy and sassy and sort of debonair.

2015 February 12, Jon Ronson, “How One Stupid Tweet Blew Up Justine Sacco’s Life”, in The New York Times‎

The hard launch of what appeared to be the hottest new relationship in town – Billanna? Winty? – at the 2023 Met Gala saw Vogue supremo Wintour, who has hosted the Met Gala for 30 years, walk the red carpet arm in arm with the dashing and debonair Love Actually star, a man Clive James named “the nation’s leading male sexpot”.

2023 May 2, Samuel Fishwick, “The ‘secret romance’ that got everybody talking at the Met Gala”, in The Independent‎

But yet, shall my vanity extend only to personals, such as the gracefulness of dress, my debonnaire, and my assurance—Self-taught, self-acquired, these!

1748, [Samuel Richardson], “Letter XXXI”, in Clarissa. Or, The History of a Young Lady: […], volume I, London: […] S[amuel] Richardson; […], page 196