Maureen meets Ronald, a half-wit (5)
I believe the answer is:
moron
'a half-wit' is the definition.
('moron' can be a synonym of 'half-wit')
'maureen meets ronald' is the wordplay.
'maureen' becomes 'mo' (I've seen this in other clues).
'meets' means one lot of letters go next to another.
'ronald' becomes 'ron' (I've seen this in other clues).
'mo'+'ron'='MORON'
(Other definitions for moron that I've seen before include "Simpleton" , "Clot" , "Cretin" , "Complete imbecile" , "Somewhat feeble-minded person" .)