Prepare a jack-o'-lantern (5)
I believe the answer is:
carve
'prepare a jack-o'-lantern' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for carve that I've seen before include "fashion" , "Cut (meat, stone, etc)" , "Truncheon" , "Slice (meat)" , "Attack the turkey" .)