Single aunt acted wildly, embracing husband (10)
I believe the answer is:
unattached
'single' is the definition.
(not attached to a partner)
'aunt acted wildly embracing husband' is the wordplay.
'wildly' indicates an anagram.
'embracing' is an insertion indicator.
'husband' becomes 'h'.
'aunt'+'acted'='auntacted'
'auntacted' is an anagram of 'unattaced'.
'unattaced' placed around 'h' is 'UNATTACHED'.
(Other definitions for unattached that I've seen before include "Not married" , "Not joined" , "Single" , "Not belonging" , "independent" .)