Essence in article recalled acrimony (6)
I believe the answer is:
animus
'acrimony' is the definition.
(thesaurus)
'essence in article recalled' is the wordplay.
'essence' becomes 'sum' ('sum' can be a synonym of 'essence').
'article' becomes 'a' (indefinite article).
'recalled' shows that the letters should be reversed in order.
'sum'+'in'+'a'='sumina'
'sumina' reversed gives 'ANIMUS'.
(Other definitions for animus that I've seen before include "US man I turn to with hostility" , "A feeling of ill will or hostility" , "Deep-seated hostility or vital force" , "Hostility, ill-feeling" , "Bad blood" .)