Noah Webster
Improper
IMPROP'ER, adjective [Latin improprius; in and proprius, proper.]
1. Not proper; not suitable; not adapted to its end; unfit; as an improper medicine for a particular disease; an improper regulation.
2. Not becoming; not decent; not suited to the character, time or place; as improper conduct in church; improper behavior before superiors; an improper speech.
3. Not according to the settled usages or principles of a language; as an improper word or phrase.
4. Not suited to a particular place or office; unqualified; as, he is an improper man for the office.