Terrible just losing face (5)
I believe the answer is:
awful
'terrible' is the definition.
(I know that terrible can be written as awful)
'just losing face' is the wordplay.
'just' becomes 'lawful' (showing justice).
'losing face' means to remove the first letter.
'lawful' with its initial letter taken off is 'AWFUL'.
(Other definitions for awful that I've seen before include "Dreadful, nasty" , "rubbish" , "Very embarrassing" , "Atrocious, dire" , "Dreadful and dire" .)