monsieur

mister, sir (a title or form of address for a man, used with or without the name in direct or third-person address); gentleman

“Il y a un monsieur pour vous voir.” — There's a gentleman here to see you.

From mon (“my”) + sieur, from the oblique case of Old French sire (cf. also seignor), ultimately from Latin senior. The first syllable has been reduced through frequent use. Loss of word-final /r/ was common in Early Modern French, but failed to establish itself except in the morphemes -er and -ier. Monsieur and gars are two relics of this pronunciation habit.