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
CTE Construction ("Core Curriculum: Introductory Craft Skills,") Vocabulary from Module One
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im-
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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.
Improper signaling or failure to use signals at all was the most common complaint we heard from readers.
From Los Angeles Times • Dec. 23, 2025
Improper use of insecticides is a health risk to people who may be overexposed to the chemicals.
From Science Daily • May 1, 2024
Improper payments are, to put it bluntly, checks that shouldn’t have been sent.
From Washington Times • Jun. 12, 2023
Improper handling of these documents should be a serious offense.
From Slate • Jan. 19, 2023
“She’s Mafalda Hopkirk,” he said, reading a small card that identified their victim as an assistant in the Improper Use of Magic Office.
From "Harry Potter and the Deathly Hallows" by J.K. Rowling
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
