Defensible points accepted by board (7)
I believe the answer is:
tenable
'defensible' is the definition.
(thesaurus)
'points accepted by board' is the wordplay.
'points' becomes 'en'.
'accepted by' is an insertion indicator.
'board' becomes 'table' ('table' can be a synonym of 'board').
'en' put into 'table' is 'TENABLE'.
(Other definitions for tenable that I've seen before include "Can be maintained" , "Able to be believed" , "Viable" , "okay as regards defence" , "Late Ben (anag.)" .)