Story that is written by learner (3)
I believe the answer is:
lie
'story' is the definition.
(story can mean a fabrication)
'that is written by learner' is the wordplay.
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'written by' is a charade indicator (letters next to each other).
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'ie' after 'l' is 'LIE'.
(Other definitions for lie that I've seen before include "A white one is considered harmless" , "Perjure" , "Be prostrate" , "Falsity" , "Tell tales" .)