Thesaurus.com
Dictionary.com
Definitions

improper

[im-prop-er] / ɪmˈprɒp ər /
ADJECTIVE
not suitable
Synonyms
STRONGEST
awkward erroneous false ill-advised imprudent inaccurate inadmissible inappropriate incorrect irregular unwarranted wrong
WEAK
abnormal at odds bad form discordant discrepant ill-timed inadvisable inapplicable inapposite inapt incongruous inexpedient infelicitous inharmonious inopportune ludicrous malapropos odd off-base out of place out-of-season preposterous unapt unbefitting uncalled-for uncomely undue unfit unfitting unseasonable unsuitable unsuited untimely
Antonyms
STRONGEST
OK acceptable accurate appropriate correct honest reasonable right suitable true valid wise
WEAK
de rigueur decent fitting formal good moral proper uncorrupt
ADJECTIVE
vulgar, immoral
Synonyms
STRONGEST
indecent unethical unjust unseemly untoward wrong wrongful
WEAK
blue dirty impolite indecorous indelicate lewd malodorous naughty risqué rough salacious suggestive unbecoming unconventional unequitable ungodly unrighteous unrightful
Antonyms
STRONGEST
acceptable appropriate decent ethical fair good honest just moral proper right suitable
WEAK
correct fitting formal uncorrupt

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.

This regulation is critical because improper activation of LypABC can be highly toxic to bacterial cells.

From Science Daily • Apr. 17, 2026

In October 2025, Organon CEO Kevin Ali resigned after an internal board investigation found what the drugmaker called improper sales practices aimed at boosting quarterly results in recent years.

From Barron's • Apr. 10, 2026

Critics said his appearance was an improper effort to influence the court ahead of a decision that will have major repercussions for his domestic policy agenda.

From BBC • Apr. 1, 2026

Other suspected fraud schemes involve enrolling beneficiaries without their consent and improper billing practices.

From MarketWatch • Mar. 24, 2026

From the beginning I was aware that there was something improper about the way I felt about Clementine Stark, something I shouldn’t tell my mother, but I wouldn’t have been able to articulate it.

From "Middlesex: A Novel" by Jeffrey Eugenides

Vocabulary lists containing improper

CTE Construction ("Core Curriculum: Introductory Craft Skills,") Vocabulary from Module One

Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!

im-

Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!

Way Off: Synonyms for "Wrong"

Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!