Rang monk at the centre, after a while (4)
I believe the answer is:
anon
'after a while' is the definition.
(I've seen this in another clue)
'rang monk at the centre' is the wordplay.
'rang' becomes 'an' (I can't justify this - if you can you should believe this answer much more).
'at the centre' says to take the centre.
The centre of 'monk' is 'on'.
'an'+'on'='ANON'
Can you help me to learn more?
(Other definitions for anon that I've seen before include "In the near future" , "Nameless - presently" , "Incognito (abbrev)" , "Some time soon" , "Shortly; unknown" .)