It's just about learner showing aptitude (5)
I believe the answer is:
flair
'aptitude' is the definition.
(flair is a kind of aptitude)
'it's just about learner' is the wordplay.
'it's just' becomes 'fair' ('fair' is associated in meaning with 'just').
'about' means one lot of letters goes inside another.
'learner' becomes 'l'.
'fair' enclosing 'l' is 'FLAIR'.
'showing' acts as a link.
(Other definitions for flair that I've seen before include "Faculty" , "gift" , "Stylishness; talent" , "Intuitive discernment" , "Talent; elegance" .)