Those who lost ground have it to make up (6)
I believe the answer is:
leeway
'make up' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for leeway that I've seen before include "Margin of safety" , "Amount of freedom" , "Margin allowing room for manoeuvre" , "Space for free movement" , "Room to manoeuvre, as for a ship" .)