Check literature about married setter (5)
I believe the answer is:
limit
'check' is the definition.
(limiting is a kind of checking)
'literature about married setter' is the wordplay.
'literature' becomes 'lit'.
'about' means one lot of letters goes inside another.
'married' becomes 'm'.
'setter' becomes 'i' (the person that set the crossword).
'm'+'i'='mi'
'lit' going around 'mi' is 'LIMIT'.
(Other definitions for limit that I've seen before include "border" , "maximum number" , "Frontier" , "qualify?" , "Furthest bound" .)