Related to a charitable cardinal, perhaps (7)
I believe the answer is:
kindred
'related' is the definition.
(synonyms)
'charitable cardinal perhaps' is the wordplay.
'charitable' becomes 'kind' (I've seen this in another clue).
'cardinal perhaps' becomes 'red' (cardinal is a kind of red).
'kind'+'red'='KINDRED'
'to a' is the link.
(Other definitions for kindred that I've seen before include "Related; similar in kind" , "clan" , "Relatively" , "Closely related" , "Family and relations" .)