That agrees with some standard or principle of correctness; consonant with the facts; correct, true.

That conforms to a required or agreed standard; right in amount, proportion, aesthetic quality, etc.; appropriate, correct.

With limitation (usually expressed by the or a possessive) to particular instances: The true or real… Proper, correct. Obsolete. rare.

Conformable to established order or rule; proper. Obsolete.

Of a polygon: = regular, adj. 2b. Obsolete.

Conducted or viewed in accordance with a rule or rules.

Made in proper form, regular, complete. Also in familiar use, ‘regular’, unmistakable. Obsolete.

Formal; regular; uniform. Obsolete.

That conforms to some accepted or adopted rule or standard; made or done in a prescribed manner; formally correct.

Exactly regular. Now rare.

Relating to, of the nature of, or according to regulations.

Linguistics. Of a word, form, or feature: having mutated or developed according to a particular rule; regular.