Webster's Revised Unabridged Dictionary · 1913

Cavalier

Cavalier (kav`ȧ*lēr") , noun

[French cavalier, Italian cavaliere, Late Latin caballarius, from Latin caballus. See Cavalcade, and compare Chevalier, Caballine.]

1.
A military man serving on horseback; a knight.
2.
A gay, sprightly, military man; hence, a gallant.
3.
One of the court party in the time of king Charles I. as contrasted with a Roundhead or an adherent of Parliament. — Clarendon
4.
(Fortification) A work of more than ordinary height, rising from the level ground of a bastion, etc., and overlooking surrounding parts.

Cavalier , adjective

offhand; unceremonious; gay; easy; frank. Opposed to serious.
The plodding, persevering scupulous accuracy of the one, and the easy, cavalier, verbal fluency of the other, form a complete contrast.
2.
High-spirited. [Obsolete]
The people are naturally not valiant, and not much cavalier. — Suckling
3.
Supercilious; haughty; disdainful; curt; brusque.
4.
Of or pertaining to the party of King Charles I.
An old Cavalier family. — Beaconsfield