A little reminder, for example, to ask repeatedly for money back (5)
I believe the answer is:
nudge
'a little reminder' is the definition.
'nudge' can be an answer for 'reminder' (I've seen this in another clue). I am not sure about the 'a little' bit.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for nudge that I've seen before include "Prod gently with elbow" , "Jogger" , "Slight push" , "Give a reminder" , "Dig with elbow" .)