Active principle of burning liquid makes strong alcohol (9)
I believe the answer is:
firewater
'strong alcohol' is the definition.
(I've seen this before)
'active principle of burning liquid' is the wordplay.
I cannot really see how this works, but
'active' could be 'a' (grammatical abbreviation) and 'a' is located in the answer.
'burning' could be 'fire' (fire is a kind of burning) and 'fire' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'makes' is the link.
Can you help me to learn more?
(Other definitions for firewater that I've seen before include "stiff drink" , "Strong alcoholic spirits" , "Strong spirit" , "whisky" , "Strong alcohol" .)