Holds good bastion in the wars (7)
I believe the answer is:
obtains
'holds' is the definition.
('obtain' can be a synonym of 'hold')
'good bastion in the wars' is the wordplay.
'bastion' anagrams to 'OBTAINS'.
However, I am not clear how this is indicated.
Can you help me to learn more?
(Other definitions for obtains that I've seen before include "Authority" , "Gets" .)