You could say Faux Bob's a slithery criminal (9)
I believe the answer is:
hairstyle
'you could say faux bob's' is the definition.
I can't tell whether this defines the answer.
'a slithery criminal' is the wordplay.
'criminal' is an anagram indicator.
'a'+'slithery'='aslithery'
'aslithery' is an anagram of 'HAIRSTYLE'.
Can you help me to learn more?
(Other definitions for hairstyle that I've seen before include "DA possibly" , "Pageboy or bob, say" , "Design of crowning glory" .)