Indecorous (8)
I believe the answer is:
unseemly
'indecorous' is the definition.
(I know that indecorous can be written as unseemly)
This is all the clue.
(Other definitions for unseemly that I've seen before include "Unbecoming, impolite" , "Unbecoming, not fitting" , "Indecent" , "Indecorous, unbecoming" , "Not decorous or fitting" .)