French word malpropre comes from French propre, French mal-

Detailed word origin of malpropre

Dictionary entry	Language	Definition
propre	French (fra)	(before a noun) own. (followed by the preposition à) proper to, specific to, particular to. (mathematics) eigen-. Clean. House-trained.
mal-	French (fra)	Badly; wrongly. Denotes the opposite of the unprefixed form.
malpropre	French (fra)	Unclean.

Words with the same origin as malpropre