The fool puts the learner in a spot (4)
I believe the answer is:
dolt
'the fool' is the definition.
(I've seen this before)
'the learner in a spot' is the wordplay.
'the learner' becomes 'l' (as in a learner driver with L-plates on their car).
'in' is an insertion indicator.
'a spot' becomes 'dot' (I've seen this before).
'l' inserted into 'dot' is 'DOLT'.
'puts' is the link.
(Other definitions for dolt that I've seen before include "Dull or stupid fellow" , "Idiot" , "Slow-witted type" , "Dimwit" , "Dunce" .)