Corner Belfast revolutionary (5)
I believe the answer is:
niche
'corner' is the definition.
('niche' can be a synonym of 'corner')
'belfast revolutionary' is the wordplay.
'belfast' becomes 'ni' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'ni'+'che'='NICHE'
Can you help me to learn more?
(Other definitions for niche that I've seen before include "Nook or recess" , "Small recess or cranny" , "Recess; place in life" , "A small recess or easy job" , "Chine (anag) - suitable place in life" .)