Mérida mister (5)
I believe the answer is:
senor
'merida mister' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for senor that I've seen before include "Gentlemanly address in Spain" , "Spanish chap" , "Snore like Spanish gent" , "'Mister' in Spain" , "Norse (anag.)" .)