Just cut doubles on court and play off and on (7)
I believe the answer is:
exactly
'just' is the definition.
(I know that just can be written as exactly)
'cut doubles on court and play off and on' is the wordplay.
'cut doubles on' becomes 'exa' (I can't justify this - if you can you should believe this answer much more).
'court' becomes 'ct' (abbreviation used in road names).
'and' says to put letters next to each other.
'off and on' means one should take alternating letters (letters used at regular intervals).
The alternate letters of 'play' are 'ly'.
'exa'+'ct'+'ly'='EXACTLY'
Can you help me to learn more?
(Other definitions for exactly that I've seen before include "On the button" , "in nice way" , "Precisely thus" , "In precise terms" , "how one might express agreement?" .)