Similar to a family (4)
I believe the answer is:
akin
'similar to' is the definition.
(I've seen this in another clue)
'a family' is the wordplay.
'family' becomes 'kin' (synonyms).
'a'+'kin'='AKIN'
(Other definitions for akin that I've seen before include "Similar in quality" , "Similar, like" , "Of like nature or related" , "Close" , "Having similar characteristics" .)