conduct 'unbecoming' an officer [=conduct/behavior that is not appropriate for an officer]
behavior 'unbecoming of/to' a public official
That color is very 'unbecoming' on her.
(..) Where's Jack? Probably stuck in some checkpoint, somewhere. You two hooked up yet? Hello, I work with him. I'm not that girl that fucks. It's unbecoming. So, a little fooling around wouldn't hurt you. Hmph... - So, no boyfriend? - Mm-mm. (..)2012 Zero Dark Thirty