It's all wound up (4)
'it's all wound up' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for coil that I've seen before include "Series of concentric circles" , "Curl, loop" , "Wind round and round in loops" , "Helix" , "Curl, spiral" .)
(Other definitions for spool that I've seen before include "Loops around with reel" , "Ribbon holder" , "On which film is wound" , "Cylinder for winding film etc" , "Bobbin, reel" .)