Thorny shrub that can be cut by a lively person? (5)
I believe the answer is:
caper
This clue is a double definition.
'thorny shrub' is the first definition.
'that can be cut by a lively person?' is the second definition.
(as in the phrase 'cut a caper')
(Other definitions for caper that I've seen before include "game" , "Cooked and pickled flower bud" , "High-spirited escapade" , "Frolic - bud used in cooking" , "Jump about playfully" .)