PROPER a.
Befitting one's nature, qualities, etc.; suitable in all respect; appropriate; right; fit; decent; as, water is the proper element for fish; a proper dress. The proper study of mankind is man. Pope. In Athens all was pleasure, mirth, and play, All proper to the spring, and sprightly May. Dryden.
PROPRIETY n.
The quality or state of being proper; suitableness to an acknowledged or correct standard or rule; consonance with established principles, rules, or customs; fitness; appropriateness; as, propriety of behavior, language, manners, etc. "The rule of propriety," Locke.