Draw level with Nick on horseback (5,2)
I believe the answer is:
catch up
'draw level' is the definition.
(I've seen this before)
'with nick on horseback' is the wordplay.
'with' says to put letters next to each other.
'nick' becomes 'catch' (I can't justify this - if you can you should give a lot more credence to this answer).
'on horseback' becomes 'up' (up can mean up on a horse).
'catch' next to 'up' is 'CATCH-UP'.
Can you help me to learn more?
(Other definitions for catch up that I've seen before include "Lag no longer" , "Regain equality" , "Draw level" , "Do things which should have been done earlier" , "Backward student must try to do this" .)