Cavalier means offhand about matters that deserve care. A cavalier attitude, cavalier with the facts, cavalier disregard.
It is always a criticism: being cavalier means treating something serious as though it were not, and it is a favourite word of inquiries and inspectors. Cavalier with the truth is the polite formula for lying. Capitalised, the Cavaliers were the royalist side in the English Civil War, and the modern sense comes from the dash and arrogance their opponents attributed to them.
1adjectivecavalierOffhand about matters that deserve care.
“His cavalier attitude to safety, like climbing without a helmet, worried his friends.”
synonyms: offhand, dismissive
cavalier is a quality of carelessness.
Middle French cavalier meant a horseman, from Latin caballus, a horse. Chivalry, cavalry and chevalier come from the same horse, and the dismissive sense comes from the Civil War royalists.
roa-oit
cavaliere
Middle French
cavalier
English, today
cavalier
Borrowed from Middle French cavalier, from roa-oit cavaliere. First appears c. 1562 in a translation by Peter Whitehorne. Borrowed from Middle French cavalier (“horseman”), itself borrowed from roa-oit cavaliere (“mounted soldier, knight”), borrowed from Old Occitan cavalier, from Latin caballārius (“horseman”), from Latin caballus (“horse”), probably from Gaulish caballos 'nag', variant of cabillos (compare Welsh ceffyl, Breton kefel, Irish capall), akin to German (Swabish) Kōb 'nag' and cu кобꙑла 'mare'. Previous English forms include cavalero and cavaliero. a doublet of caballero and chevalier.
Etymology from Wiktionary, CC BY-SA