1. [ adjective ] not suitable or right or appropriate

"slightly improper to dine alone with a married man" "improper medication"

Related terms: proper indecent wrong out-of-the-way out-of-the-way inappropriate incorrect wrong inappropriate unfit indecent indecorous propriety
2. [ adjective ] not conforming to legality, moral law, or social convention
Synonyms: unlawful unconventional

"an unconventional marriage" "improper banking practices"

Related terms: irregular
3. [ adjective ] not appropriate for a purpose or occasion
Synonyms: wrong unsuitable

"unsuitable attire for the office" "said all the wrong things"

Related terms: inappropriate
Similar spelling:   improperly