Close family wrapping son in fur (8)
I believe the answer is:
sealskin
'fur' is the definition.
(sealskin is a kind of fur)
'close family wrapping son' is the wordplay.
'close' becomes 'seal' (sealing is a kind of closing).
'family' becomes 'kin' (synonyms).
'wrapping' means one lot of letters goes inside another.
'son' becomes 's' (genealogical abbreviation for son).
'seal'+'kin'='sealkin'
'sealkin' enclosing 's' is 'SEALSKIN'.
'in' is the link.
(Other definitions for sealskin that I've seen before include "Hide" , "Fur from the sea" , "Fur - lean kiss (anag)" , "prepared fur" , "Form of fur for garments" .)