improper
Americanadjective
-
not proper; not strictly belonging, applicable, correct, etc.; erroneous.
He drew improper conclusions from the scant evidence.
- Synonyms:
- unfit, unsuited, inapplicable
-
not in accordance with propriety of behavior, manners, etc..
improper conduct at a funeral.
- Synonyms:
- indecorous, unfit, unsuited, inapplicable
- Antonyms:
- proper
-
unsuitable or inappropriate, as for the purpose or occasion.
improper attire for a formal dance.
- Synonyms:
- unfit, unsuited, inapplicable
-
abnormal or irregular.
improper functioning of the speech mechanism.
adjective
-
lacking propriety; not seemly or fitting
-
unsuitable for a certain use or occasion; inappropriate
an improper use for a tool
-
irregular or abnormal
Usage
What does improper mean? Improper describes something considered unsuitable or inappropriate for the purpose or occasion, as in A ballgown is improper dress for playing basketball. Improper also describes something that isn’t appropriate for a specific scenario or circumstance, as in Shouting out the answers during a silent test is generally considered improper. Improper can also describe something that is not correct, such as with an inaccurate conclusion or faulty language usage. Finally, improper can be used to describe something as abnormal or irregular, particularly in reference to how something mechanical operates. Example: We knew the test readouts were improper because the results were physically impossible.
Synonym Usage
Improper, indecent, unbecoming, unseemly are applied to that which is unfitting or not in accordance with propriety. Improper has a wide range, being applied to whatever is not suitable or fitting, and often specifically to what does not conform to the standards of conventional morality: improper diet; improper behavior in church; improper language. Indecent, a strong word, is applied to what is offensively contrary to standards of propriety and especially of modesty: indecent behavior, literature. Unbecoming is applied to what is especially unfitting in the person concerned: conduct unbecoming a minister. Unseemly is applied to whatever is unfitting or improper under the circumstances: unseemly mirth.
Other Word Forms
Etymology
Origin of improper
From the Latin word improprius, dating back to 1535–45. See im- 2, proper
Explanation
Improper words and actions are inappropriate. They're not suited to the occasion or done in polite company. They’re just not proper! Surprise! Improper is the opposite of proper. Something that’s improper goes against what people think is right. This could be a matter of politeness. For example, not giving up your seat for an elderly person is improper. Or it could be more serious, like going to school with no pants on. It could also be something uncool like meeting your best friend’s boyfriend for coffee without telling her. All improper things are wrong in someone's eyes.
Vocabulary lists containing improper
im-
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CTE Construction ("Core Curriculum: Introductory Craft Skills,") Vocabulary from Module One
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Way Off: Synonyms for "Wrong"
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The statement did not say whether any fraud or improper payments had been discovered.
From MarketWatch ● Oct. 20, 2026
The information in the report is, rather, “only a selection of cases we have investigated as a deterrent for state agencies and state employees so they can avoid similar improper governmental activities,” the audit said.
From Los Angeles Times ● Oct. 8, 2026
"Etihad categorically rejects any finding, conclusion or implication that suggests the airline has ever been involved in improper commercial arrangements," an Etihad spokesperson said in a statement released late Wednesday.
From Barron's ● Oct. 1, 2026
Harshey-Jones also pleaded guilty to a charge of corrupt or improper exercise of his police powers and privileges by looking up his own incident on the computer log.
From BBC ● Sep. 30, 2026
“What an extraordinary thing! I always thought dancing improper, but it can’t be since I myself am dancing. For I am a model cow.”
From "Mary Poppins" by P. L. Travers
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Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
