To prevaricate is the last chance for a learner (5)
I believe the answer is:
stall
'to prevaricate' is the definition.
(thesaurus)
'the last chance for a learner' is the wordplay.
'the last chance for' becomes 'stal' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a learner' becomes 'l' (as in a learner driver with L-plates on their car).
'stal'+'l'='STALL'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for stall that I've seen before include "Booth; prevaricate" , "Cowshed or stable" , "(Of engine) stop running; booth" , "Animal compartment" , "Box" .)