adjective
indecent
in-DEE-sunt/ɪnˈdiːsnt/
Offensive to accepted standards of decency or proper behavior.
The dinner guest makes an indecent gesture that shocks the others.

Etymology
The underlying idea is something that is not fitting or suitable. From the broader meaning “unbecoming” or “in bad taste,” the adjective came to describe what offends against propriety.
In context
She felt so miserably undressed in its low neck and short sleeves. And that low, crimson girdle around the hips seemed positively indecent.
More examples
- She condemned the indecent remark.
- The conduct was indecent.
- They rejected the indecent proposal.
Forms
indecent
indecency noun — behavior violating accepted standards