Comportment (4)
'comportment' is the definition.
(I know that comportment can be written as mien)
This is all the clue.
(Other definitions for mien that I've seen before include "aspect" , "(One's) manner, bearing" , "Appearance is strangely mine" , "Dignified manner" , "A face - maybe mine" .)
'comportment' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Another definition for demeanor that I've seen is " American appearance in Britain".)