Showing off a snake bite? (8)
I believe the answer is:
boasting
'showing off' is the definition.
(I've seen this before)
'a snake bite?' is the wordplay.
'a snake' becomes 'boa' (boa is a kind of snake).
'bite?' becomes 'sting' ('sting' can be a synonym of 'bite').
'boa'+'sting'='BOASTING'
(Other definitions for boasting that I've seen before include "Preening" , "Talking conceitedly" , "Bragging, showing off" .)