Learner gets it - he's flexible (5)
I believe the answer is:
lithe
'flexible' is the definition.
(I've seen this before)
'learner gets it he's' is the wordplay.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'gets' is a charade indicator (letters next to each other).
'l'+'it'+'he'='LITHE'
(Other definitions for lithe that I've seen before include "flex with no difficulty" , "Moving and bending with ease" , "able to move supply" , "Lissom, supple" , "Elastic" .)