One into gin drunkenly finds point of combustion (8)
I believe the answer is:
ignition
'point of combustion' is the definition.
(I've seen this before)
'one into gin drunkenly' is the wordplay.
'one' becomes 'i' (Roman numeral).
'drunkenly' indicates anagramming the letters.
'into'+'gin'='intogin'
'intogin' anagrammed gives 'gnition'.
'i'+'gnition'='IGNITION'
'finds' acts as a link.
(Other definitions for ignition that I've seen before include "Moment of setting something alight" , "Beginning of combustion" , "Point at which combustion occurs" , "Mechanism used to start an engine" , "The purpose of the spark" .)