Show of intelligence in school will get you the cane (6)
I believe the answer is:
switch
'the cane' is the definition.
(I've seen this before)
'show of intelligence in school' is the wordplay.
I cannot quite understand how this works, but
'intelligence' could be 'wit' (wit is a kind of intelligence) and 'wit' is found in the answer.
'school' could be 'sch' (common abbreviation) and 'sch' is present in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'will get you' is the link.
Can you help me to learn more?
(Other definitions for switch that I've seen before include "Change position" , "Change; flexible shoot" , "Cane to control the light" , "Swap" , "that turns on the power" .)