Not all learners will show merit (4)
I believe the answer is:
earn
'merit' is the definition.
(thesaurus)
'not all learners will' is the wordplay.
'not all' indicates the answer is hidden within the clue.
'EARN' is hidden in the letters of 'learners will'.
'show' acts as a link.
(Other definitions for earn that I've seen before include "Obtain (money) in return for labour or services" , "Merit through work or endeavour" , "Merit (a reward)" , "There's merit" , "Acquire money by labour" .)