Dispute about learner making crashing sound (5)
I believe the answer is:
splat
'sound' is the definition.
(splatting is a kind of sounding)
'dispute about learner' is the wordplay.
'dispute' becomes 'spat' (spat is a kind of dispute).
'about' is an insertion indicator.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'spat' going around 'l' is 'SPLAT'.
'making crashing' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for splat that I've seen before include "Sound of a soft wet landing" , "Sound of a soft, wet object striking a surface" , "amusing noise" , "Noise on landing" , "Noise of soft wet impact; part of a chair back" .)