Liven up foolish cunning (7)
I believe the answer is:
vulpine
'cunning' is the definition.
(I've seen this before)
'liven up foolish' is the wordplay.
'foolish' indicates anagramming the letters (a foolish spelling).
'liven'+'up'='livenup'
'livenup' is an anagram of 'VULPINE'.
(Other definitions for vulpine that I've seen before include "like Basil Brush?" , "Resembling a fox" , "Relating to foxes" , "Being foxy" , "Cunning as a fox - liven up (anag)" .)