Improves, as skills (5)
I believe the answer is:
hones
'improves as skills' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for hones that I've seen before include "Perfects, sharpens" , "Sharpens, like knife on stone" , "gets sharp" , "Sharpens on strap, say razor" , "Sharpens as on whetstone" .)