Nurse leant on a roll (8)
I believe the answer is:
enlisted
'on a roll' is the definition.
(I've seen this before)
'nurse leant' is the wordplay.
'nurse' becomes 'EN' (abbreviation for state-enrolled nurse).
'leant' becomes 'listed' (I can't explain this - if you can you should give a lot more credence to this answer).
'en'+'listed'='ENLISTED'
Can you help me to learn more?
(Other definitions for enlisted that I've seen before include "On a roll" , "Listened (anag.)" , "Signed up" , "Joined the military" , "Joined up (milit.)" .)