Bottle -- what could be in it? (6)
I believe the answer is:
spirit
'bottle' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for spirit that I've seen before include "Liquor or spectre" , "verve" , "Jinn" , "Incorporeal supernatural being" , "Mood - ghost - alcohol" .)