Leader means to make progress (7)
I believe the answer is:
headway
'make progress' is the definition.
(I've seen this before)
'leader means' is the wordplay.
'leader' becomes 'head' (head is a kind of leader).
'means' becomes 'way' ('way' can be a synonym of 'means'**).
'head'+'way'='HEADWAY'
'to' is the link.
(Other definitions for headway that I've seen before include "Progress or forward motion" , "Advance" , "make progress" , "Progress, forward movement" , "Ground" .)