Improper and Unacceptable

Improper

Improper adjective - Not appropriate for a particular occasion or situation.
Usage example: an improper use of slang in a formal piece of writing

Unacceptable is a synonym for improper in inappropriate topic. In some cases you can use "Unacceptable" instead an adjective "Improper".

Nearby Word: improperly

Unacceptable

Unacceptable adjective - Falling short of a standard.

Improper is a synonym for unacceptable in offensive topic. You can use "Improper" instead an adjective "Unacceptable", if it concerns topics such as not suitable or satisfactory.

Nearby Word: unaccepted
Cite this Source
Unacceptable and Improper. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/improper/unacceptable
Improper & Unacceptable. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/improper/unacceptable>.
Unacceptable or Improper. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/improper/unacceptable.
Google Ngram Viewer shows how "improper" and "unacceptable" have occurred on timeline