Gaunt-looking rogue: suave or devious? (10)
I believe the answer is:
cadaverous
'gaunt-looking' is the definition.
(looking like a cadaver)
'rogue suave or devious?' is the wordplay.
'rogue' becomes 'cad' (I've seen this before).
'devious?' indicates anagramming the letters (I've seen 'devious' mean this).
'suave'+'or'='suaveor'
'suaveor' anagrammed gives 'averous'.
'cad'+'averous'='CADAVEROUS'
(Other definitions for cadaverous that I've seen before include "Ghastly" , "Unhealthy-looking" , "Skeletal" , "Gaunt" , "not looking healthy" .)