Embrace uncle I'd mistreated (7)
I believe the answer is:
include
'embrace' is the definition.
(thesaurus)
'uncle i'd mistreated' is the wordplay.
'mistreated' is an anagram indicator.
'uncle'+'id'='uncleid'
'uncleid' with letters rearranged gives 'INCLUDE'.
(Other definitions for include that I've seen before include "Have within" , "Allow participation in" , "Take as part of a group" , "Comprise, contain" , "Add as part of something else" .)