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.

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. im•prop′er•ness, n.

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

improper adjective (WRONG) unsuitable or not correct for a particular use or occasion: improper prescription of medicines

If you describe someone's behavior as improper, you mean it is rude or shocking or in some way socially unacceptable. Such improper behavior and language from a young lady left me momentarily …

unsuitable or inappropriate, as for the purpose or occasion: improper attire for a formal dance. abnormal or irregular: improper functioning of the speech mechanism.

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