Some turn to gin (4)
'gin' is the definition.
(I've seen this before)
'some turn' is the wordplay.
'some' becomes 'part'.
'turn' says the letters should be written in reverse.
'part' in reverse letter order is 'TRAP'.
'to' is the link.
(Other definitions for trap that I've seen before include "fault", "Lock", "Deceive", "Light carriage - it's sometimes sprung!", "Snare - mouth".)