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 definition: not proper; not strictly belonging, applicable, correct, etc.; erroneous.. See examples of IMPROPER used in a sentence.

improper adjective (WRONG) not suitable or correct for a particular use or situation: an improper choice of words

Improper conditions or methods of treatment are not suitable or good enough for a particular purpose.

1. not proper; not strictly belonging, applicable, or correct: drew improper conclusions. 2. not in accordance with propriety or regulations: improper conduct. 3. abnormal; irregular.

Definition of improper adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

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; …

Sep 23, 2025 · improper (comparative more improper, superlative most improper) Unsuitable to needs or circumstances; inappropriate; inapt. Not in keeping with conventional mores or good …

How does the adjective improper differ from other similar words? Some common synonyms of improper are indecorous, indelicate, unbecoming, and unseemly.

There are five meanings listed in OED's entry for the adjective improper, one of which is labelled obsolete. See ‘Meaning & use’ for definitions, usage, and quotation evidence.