Natural ability shown by learner in market (5)
I believe the answer is:
flair
'natural ability' is the definition.
(flair is a kind of natural ability)
'learner in market' is the wordplay.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'in' means one lot of letters goes inside another.
'market' becomes 'fair' (I've seen this before).
'l' going into 'fair' is 'FLAIR'.
'shown by' is the link.
(Other definitions for flair that I've seen before include "Bent" , "Taste" , "skill" , "Style, talent" , "Elan; panache" .)