improper

 
Pronunciation: /ɪmˈprɒpə/

adjective

  • not in accordance with accepted standards, especially of morality or honesty: the improper use of public funds it was considered improper to leave one’s house on Christmas Day
  • lacking in modesty or decency: an improper suggestion

Derivatives

improperly

adverb

Origin:

late Middle English: from French impropre or Latin improprius, from in- 'not' + proprius 'one's own, proper'