Letting learner relax (5)
I believe the answer is:
lease
'letting' is the definition.
('lease' can be a synonym of 'letting')
'learner relax' is the wordplay.
'learner' becomes 'l'.
'relax' becomes 'ease' (I've seen this before).
'l'+'ease'='LEASE'
(Other definitions for lease that I've seen before include "Let; rent" , "Let out, hire" , "Contract for, say, use of building" , "Contract to rent" , "Tenancy agreement" .)