Crime engendering much heatedness (5)
I believe the answer is:
arson
'crime' is the definition.
(crime of illegally starting a fire)
'engendering much heatedness' is the wordplay.
I cannot really see how this works, but
'much' could be 'so' (similar in meaning) and 'so' is located in the answer.
The remaining letters 'arn' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for arson that I've seen before include "Fire-lighting crime" , "Act of a pyromaniac" , "Illegally firing" , "Pyromaniac crime" , "Criminal pyromania" .)