A learner restricted by paltry grant (5)
I believe the answer is:
allow
'grant' is the definition.
(I know that grant can be written as allow)
'a learner restricted by paltry' is the wordplay.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'restricted by' means one lot of letters goes inside another (I've seen this in other clues).
'paltry' becomes 'low' (as in a paltry sum).
'l' put inside 'low' is 'llow'.
'a'+'llow'='ALLOW'
(Other definitions for allow that I've seen before include "Admit as acceptable" , "OK" , "Give permission to" , "Acknowledge - concede" , "Permit, consent to" .)