Head over heels, tried again to make the grade - it's shocking! (5)
I believe the answer is:
taser
'it's shocking' is the definition.
(I've seen this in another clue)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for taser that I've seen before include "Stun gun" , "The weapon delivers a temporary paralysing electric shock" , "Shocking device used by the police?" , "A temporary stunner?" , "Gun firing electrified barbs" .)