What does improper mean?
Improper means not suitable, correct, or in accordance with accepted rules or standards. The word is especially common in formal, legal, and institutional contexts, where it describes improper conduct, improper use of resources, or interference with a process that should follow established procedures. It can also describe a grammatical or mathematical error: an improper fraction, for example, has a numerator equal to or greater than its denominator. Because “improper” can imply a breach of rules as well as poor suitability, it often carries a serious or disapproving tone. Its Latin origin is transparent: the word was formed from “in,” meaning “not,” and “proper,” meaning suitable or fitting. The related noun “impropriety” is especially associated with behaviour that violates social or professional standards.
adjectiveNot according to what is appropriate, correct, or suitable; improper behavior or use. In mathematics, improper describes a fraction whose numerator is equal to or greater than its denominator.
- Not suited to the circumstances; inappropriate, unsuitable, or contrary to accepted standards of behaviour.
- Not following the prescribed rules or conventions; incorrect or improper.
- In mathematics, describing a fraction whose numerator is equal to or greater than its denominator.
"The committee criticized the improper handling of confidential information."
"It would be improper to interrupt the speaker during the ceremony."
"The report identified several improper uses of company funds."
"An improper fraction can always be rewritten as a mixed number or whole number."
From Latin, improper literally meant “not proper”: a word that still announces exactly where standards have been broken.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does improper come from?
The word comes from Latin improprius, formed from the prefix in- and the adjective proprius, meaning “one's own,” “proper,” or “suitable.” It entered English in the 16th century with the sense “not proper” and was later extended to describe conduct and mathematical quantities. The same Latin root appears in words such as proper, property, propriety, and proprietary.
Related word forms
How improper is actually used
The adjective is common in formal and legal contexts. “Improper” can describe conduct, use, treatment, or mathematical quantities, while the noun “impropriety” is more often used for socially inappropriate behaviour.
Easily confused with improper
Improper is an adjective describing something that is inappropriate or not allowed, whereas impropriety is a noun referring to inappropriate behaviour or a breach of propriety.
Improper means unsuitable or contrary to what is right, while improbable means unlikely to happen or be true.