improper

adjective

im·​prop·​er (ˌ)im-ˈprä-pər 

: not proper: such as

a

: not in accord with propriety, modesty, good manners, or good taste

improper language

b

: not suited to the circumstances, design, or end

improper medicine

c

: not regularly or normally formed or not properly so called

d

: not in accord with fact, truth, or right procedure : incorrect

improper inference

improperly adverb

improperness noun

Synonyms

• inappropriate
• unsuitable
• incorrect
• wrong
• unfit
• unhappy

Choose the Right Synonym for improper

indecorous, improper, unseemly, unbecoming, indelicate mean not conforming to what is accepted as right, fitting, or in good taste.

indecorous suggests a violation of accepted standards of good manners.

indecorous behavior

improper applies to a broader range of transgressions of rules not only of social behavior but of ethical practice or logical procedure or prescribed method.

improper use of campaign contributions

unseemly adds a suggestion of special inappropriateness to a situation or an offensiveness to good taste.

remarried with unseemly haste

unbecoming suggests behavior or language that does not suit one's character or status.

conduct unbecoming to an officer

indelicate implies a lack of modesty or of tact or of refined perception of feeling.

indelicate expressions for bodily functions

Examples of improper in a Sentence

The doctor gave him an improper diagnosis.

They claim to have evidence of improper police conduct.

improper use of public land

This is an improper diet for a growing teenager.

It would be improper for me to ask such a favor of her.

He made some improper remarks.

Recent Examples on the Web

An arrest does not constitute a finding of guilt: A 29-year-old man from Lisle was arrested on charges of improper lane usage, speeding and driving under the influence of alcohol at 12:27 a.m. July 1 at East Chicago Avenue and South Naper Boulevard. —Steve Metsch, Chicago Tribune, 6 July 2025

While these tools can help employers screen more job candidates and help identify relevant experience, human resources and legal experts warn improper training and implementation of hiring technologies can proliferate biases. —Sasha Rogelberg, Fortune, 5 July 2025

Urban Corps did not respond to questions about Sierra’s claim in his resignation letter that Bernstein had sought to conceal Kennedy’s improper use of nonprofit workers to remake his personal property. —Jeff McDonald, San Diego Union-Tribune, 4 July 2025

Stay vigilant Nearly a quarter of all reported boating accidents last year were caused by operator inattention or improper lookout. —Katie Nixon, The Tennessean, 2 July 2025

Word History

Etymology

Middle English, from Middle French impropre, from Latin improprius, from in- + proprius proper

First Known Use

15th century, in the meaning defined above

Phrases Containing improper

• improper fraction
• improper integral

Rhymes for improper

• eavesdropper
• grasshopper
• leafhopper
• sharecropper
• chopper
• copper
• cropper
• dropper
• pauper
• popper
• proper
• shopper

Kids Definition

improper

adjective

im·​prop·​er (ˈ)im-ˈpräp-ər 

: not proper, right, or suitable

improperly adverb

Legal Definition

improper

adjective

im·​prop·​er

: not proper: as

a

: not in accord with correct procedure

an improper venue

b

: wrongful

specifically : in violation of a constitution

the denial of trial by jury was held improper

improperly adverb