Treasonous face admitting nothing in cunning (8)
I believe the answer is:
disloyal
'treasonous' is the definition.
('disloyal' can be similar in meaning to 'treasonous')
'face admitting nothing in cunning' is the wordplay.
I cannot quite understand how this works, but
'nothing' could be 'o' (looks like zero - 0) and 'o' is present in the answer.
'cunning' could be 'sly' ('sly' can be a synonym of 'cunning') and 'sly' is found within the remaining letters.
'face' could be 'dial' (dial is a kind of face) and 'dial' is found in the remaining letters.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for disloyal that I've seen before include "Deserting allegiance or duty" , "Not true or faithful in one's relationships" , "Faithless" , "Not faithful, unpatriotic" , "Deserting one's allegiance" .)