Man mixed gin that's harmless (6)
I believe the answer is:
benign
'harmless' is the definition.
(associated in meaning)
'man mixed gin' is the wordplay.
'man' becomes 'ben' ().
'mixed' indicates an anagram.
'gin' anagrammed gives 'ign'.
'ben'+'ign'='BENIGN'
'that's' is the link.
(Other definitions for benign that I've seen before include "'Pleasant and kind, not harmful (6)'" , "Meaning no harm" , "Obliging" , "Medically curable" , "Kindly; not harmful" .)