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 dress/attire

an improper diet

an improper diagnosis

c

: not regularly or normally formed or not properly so called

d

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

improper inference

improper use of public land

specifically : in violation of a constitution

denial of trial by jury was held improper

improperly adverb

improperness noun

Synonyms of improper

• 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

While the expiration of the enhanced ACA subsidies at the end of 2025 made insurance more expensive for millions of consumers, the HHS assistant secretary for planning and evaluation report cited efforts to crack down on improper signups. — Ken Alltucker, USA Today, 1 July 2026

The Boca View Condominium Association and its board president were the subjects of a recent article in the Palm Beach Post focusing on a lawsuit brought by a unit owner alleging improper blocking of the sale for her unit. — Nicole R. Kurtz, Miami Herald, 1 July 2026

The agency is also asking visitors to the World Cup game or Fan Fest to report any unsafe or improper drone use to the FBI tipline at 1-800-CALL-FBI. — Dan Raby, CBS News, 30 June 2026

Overloading Your Washer Even the softest of towels are not impervious to improper laundering, and overloading your washer or using too little water can affect how thoroughly the towels are washed. — Louise Parks, Martha Stewart, 30 June 2026

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