/ ˌʌnbɪˈkʌmɪŋ; NAmE / adjective ( formal )
1.
not suiting a particular person
SYN unflattering :
She was wearing an unbecoming shade of purple.
2.
unbecoming (to / of sb) not appropriate or acceptable
SYN inappropriate :
He was accused of conduct unbecoming to an officer.
OPP becoming