Helping to keep Bishop standing (7)
I believe the answer is:
abiding
'standing' is the definition.
('abide' can be a synonym of 'stand')
'helping to keep bishop' is the wordplay.
'helping' becomes 'aiding' ('aid' can be a synonym of 'help'**).
'to keep' means one lot of letters goes inside another.
'bishop' becomes 'b' (abbreviation used in chess).
'aiding' enclosing 'b' is 'ABIDING'.
(Other definitions for abiding that I've seen before include "With a lasting quality" , "bearing" , "Dwelling; enduring, lasting" , "Persisting" , "Enduring - constant" .)