Minimum rent round centre of Damascus (5)
I believe the answer is:
least
'minimum' is the definition.
('least' can be similar in meaning to 'minimum')
'rent round centre of damascus' is the wordplay.
'rent' becomes 'let'.
'round' is an insertion indicator.
'centre of' says to take the centre.
The central letters of 'damascus' are 'as'.
'let' placed around 'as' is 'LEAST'.
(Other definitions for least that I've seen before include "Smallest, slightest" , "Steal (anag)" , "Lowest or smallest" , "Being lowest in importance - gone stale" , "Most insignificant" .)