Clue to make rum link with gin (7)
I believe the answer is:
inkling
'clue' is the definition.
(I've seen this before)
'rum link with gin' is the wordplay.
'rum' indicates an anagram (rum can mean strange or unusual).
'with' is a charade indicator (letters next to each other).
'link' after 'gin' is 'ginlink'.
'ginlink' anagrammed gives 'INKLING'.
'to make' is the link.
(Other definitions for inkling that I've seen before include "Clue" , "Intimation" , "Slight suggestion or vague understanding" , "Slight hint or suspicion" , "Linking with suspicion or hint" .)