de rigueur (duh ree-GUHR)
Required by fashion, custom, or etiquette.
From 'of strictness', from the Latin rigor.
To ward off or evade.
A defensive movement or an evasive answer.
From parez which means 'ward off'
femme fatale (fem fuh-TAHL)
plural femmes fatales (fem fuh-TAHLZ)
An attractive and seductive woman, especially one who leads others into disaster.
Literally fatal woman. :D :D
A reversal in policy or opinion; about-face.
It came into French from Latin volvere (to turn) + faccia (face).
nouveau riche (noo-voh-REESH)
Someone who has recently acquired wealth, especially one who displays this in an ostentatious fashion.
The term nouveau riche in French simply means 'new rich'. Trust the French to coin another word on the same lines - 'nouveau pauvre' meaning 'newly impoverished'.