Period after court measure (7)
I believe the answer is:
yardage
'measure' is the definition.
(I've seen this before)
'period after court' is the wordplay.
'period' becomes 'age' (age is a kind of period).
'after' is a charade indicator (letters next to each other).
'court' becomes 'yard' (courtyard).
'age' put after 'yard' is 'YARDAGE'.
(Other definitions for yardage that I've seen before include "Distance covered" , "Gay dear (anag.)" , "Length in units of three feet" , "Distance measured in imperial units" , "Measurement of length" .)