Lots of married fools (6)
I believe the answer is:
masses
'lots' is the definition.
('mass' can be a synonym of 'lot')
'married fools' is the wordplay.
'married' becomes 'm'.
'fools' becomes 'asses' (ass is a kind of fool).
'm'+'asses'='MASSES'
'of' acts as a link.
(Other definitions for masses that I've seen before include "Lots, services" , "Crowds of people or religious ceremonies" , "Loads" , "The ordinary people" , "Roman Catholic ceremonies" .)