Gives a leg up (6)
I believe the answer is:
boosts
'gives a leg up' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for boosts that I've seen before include "Pushes upwards or promotes" , "Pushes upward or increases" , "Pushes or thrusts upward like a rocket" , "Increases or improves" , "Pushes or shoves upward" .)