Insult can be hell (3)
I believe the answer is:
dis
I believe this is a double definition.
'insult' is the first definition.
(shortened form of 'disrespect' - slang)
'be hell' is the second definition.
(I've seen this in other clues)
'can' acts as a link.
(Other definitions for dis that I've seen before include "Speak to (someone)without respect" , "soul venue" , "Hades" , "Show contempt" , "Treat without respect - god of the underworld" .)