cav·a·lier 
(kăv′ə-lîr)
(kăv′ə-lîr)n.
1. A gallant or chivalrous man, especially one serving as escort to a woman of high social position; a gentleman.
2. A mounted soldier; a knight.
3. Cavalier A supporter of Charles I of England in his struggles against Parliament. Also called Royalist.
adj.
1. Showing arrogant or offhand disregard; dismissive: a cavalier attitude toward the suffering of others.
2. Carefree and nonchalant; jaunty.
3. Cavalier Of or relating to a group of 17th-century English poets associated with the court of Charles I.
[French, horseman, from Old Italian cavaliere, from Late Latin caballārius, from Latin caballus, horse; akin to Greek kaballēs, work horse, both Greek and Latin probably ultimately from an Iranian source (compare Khotanese kabä, horse, and Persian kaval, a slow, clumsy horse), from Old Iranian *kaba-, *kabala-, horse, akin to Late Latin cabō, gelding, and Old Church Slavonic kobyla, mare, and perhaps ultimately of Proto-Indo-European origin.]
cav′a·lierly adv.