Maintained it's Enid's move (8)
I believe the answer is:
insisted
'maintained' is the definition.
(I've seen this before)
'it's enid's move' is the wordplay.
'move' indicates an anagram.
'its'+'enids'='itsenids'
'itsenids' anagrammed gives 'INSISTED'.
(Other definitions for insisted that I've seen before include "Declared emphatically about tidiness" , "Asserted, took a firm stand" , "... repeated" , "Maintained firmly" , "Tidiness (anag.)" .)