[Middle English debonaire, gracious, kindly, from Old French, from de bon aire, of good lineage or disposition : de, of (from Latin dē; see de-) + bon, bonne, good (from Latin bonus; see deu-2 in Indo-European roots) + aire, nest, family; see aerie.] deb'o·nair'ly adv., deb'o·nair'ness n.