(obsolete) Something set apart for a special use.
(Christianity) A part of the Christian liturgy that varies according to the date.
Suitable, following established standards of behavior or manners, continuous in topology, separated and of finite type in algebraic geometry, and such that every closed ball is compact in mathematical analysis.
An adjective "proper" is used to designate a particular person, place, or thing, pertaining exclusively to a specific thing or person, within the strict definition or core, belonging to oneself or itself, portrayed in natural coloration, and being strictly part of some other thing.
An adjective "proper" can mean accurate, of high quality, attractive, elegant, in the strictest sense, utter or complete, and not being a set in set theory.
(UK, colloquial) properly; thoroughly; completely.
(nonstandard, colloquial) properly.