impermissible
im-per-mis-si-ble
adjective
Not allowed or permitted; forbidden by rules, law, or moral principles.
"Such conduct is impermissible in this establishment."
Thesaurus
Synonyms: forbidden, unmentionable, tabu, proscribed, taboo, prohibited, untouchable, verboten, out, inadmissible
Antonyms: allowable, permissible