adjective
improper
im-PRAH-per/ɪmˈprɑːpər/
Not appropriate or acceptable under the circumstances.
Resting muddy boots on the dining table is improper behavior for a guest.

Etymology
The ancestor of proper meant “one's own” or “particular,” while proper developed the sense “fitting or appropriate.” The negative prefix makes improper its opposite: not fitting a purpose or meeting accepted standards.
In context
it can lead to an improper bite and it can also lead to your lower incisors down these teeth biting against the palate of your upper teeth and causing inflammation
More examples
- It is improper to discuss a patient's records in public.
- The audit reveals improper use of company funds.
- Such jokes are improper at a memorial service.
Forms
improper
improperly adverb — In an inappropriate or unacceptable way.
impropriety noun — Behavior that violates accepted standards of conduct.
Similar words
- inappropriate
- Often stresses a poor fit for a particular situation.
- unacceptable
- Stresses failure to meet a required standard or limit.