debonair UK /ˌdɛbəˈneə(ɹ)/US /ˌdɛbəˈnɛɹ/adjective 3noun 1forms 2 adjective3 •Suave, urbane and sophisticated.She was a New York City person. Sacco is nervy and sassy and sort of debonair. — 2015 •Charming, confident, and carefully dressed. •(no longer used) Gracious, courteous.Let be that Ladie debonaire, / Thou recreant knight, and soone thy selfe prepaire / To battell […]. — 1590 noun1 •(no longer used) Debonaire behaviour; graciousness.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 formsmore debonair · most debonair