Liable to see red snake burrowing into pine (7)
I believe the answer is:
waspish
'liable to see red' is the definition.
'snake burrowing into pine' is the wordplay.
'snake' becomes 'asp' (asp is a kind of snake).
'burrowing into' is an insertion indicator.
'pine' becomes 'wish'.
'asp' put into 'wish' is 'WASPISH'.
(Other definitions for waspish that I've seen before include "Petulant" , "Easily angered - with black and yellow stripes?" , "Spiteful (with a slender waist?)" , "Bad-tempered like striped stinger" , "Easily-provoked" .)