Animal of tenderness, say (4)
I believe the answer is:
hart
'animal' is the definition.
(I've seen this before)
'tenderness say' is the wordplay.
'tenderness' becomes 'heart' (synonyms).
'say' shows a homophone (sound like).
'heart' is a homophone of 'HART'.
'of' is the link.
(Other definitions for hart that I've seen before include "Adult male red deer" , "providing material for Richard Rodgers?" , "Ruminative type" , "Mature male deer" , "Beast" .)