• synonyms


See more synonyms for improper on Thesaurus.com
  1. not proper; not strictly belonging, applicable, correct, etc.; erroneous: He drew improper conclusions from the scant evidence.
  2. not in accordance with propriety of behavior, manners, etc.: improper conduct at a funeral.
  3. unsuitable or inappropriate, as for the purpose or occasion: improper attire for a formal dance.
  4. abnormal or irregular: improper functioning of the speech mechanism.
Show More

Origin of improper

From the Latin word improprius, dating back to 1535–45. See im-2, proper
Related formsim·prop·er·ly, adverbim·prop·er·ness, noun


See more synonyms for on Thesaurus.com
1–3. inapplicable, unsuited, unfit. 2. indecorous. 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.


1, 3. fitting, suitable. 2. proper.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for improper

Contemporary Examples

Historical Examples

British Dictionary definitions for improper


  1. lacking propriety; not seemly or fitting
  2. unsuitable for a certain use or occasion; inappropriatean improper use for a tool
  3. irregular or abnormal
Show More
Derived Formsimproperly, adverbimproperness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for improper


mid-15c., "not true," from French impropre (14c.), from Latin improprius, from assimilated form of in- "not, opposite of" (see in- (1)) + proprius (see proper). Meaning "not suited, unfit" is from 1560s; that of "not in accordance with good manners, modesty, decency" is from 1739. Related: Improperly (late 14c.).

Show More
Online Etymology Dictionary, © 2010 Douglas Harper