dishonest, illegal, or morally wrong
it is improper (for somebody) to do something
He realised that it was improper for a police officer to accept gifts.
improper behaviour/conduct/dealings etc
allegations of improper banking practices
improper sexual conduct
not sensible, right, or fair in a particular situation [= inappropriate]
it is improper to do something
It would be improper of me to comment before the election outcome is known.
wrong or not correct
If you are improperly dressed, you will not be admitted.