Aptly enough, it may be full of spirit (6)
I believe the answer is:
bottle
'spirit' is the definition.
(I have seen 'The spirit' mean 'bottle' so perhaps 'spirit' could also mean 'bottle')
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for bottle that I've seen before include "Glass or plastic container" , "Jeroboam" , "Grit" , "Here's where it's to be found" , "Vessel for liquids" .)