Bad actor for every exercise - heartless rat (11)
I believe the answer is:
perpetrator
'bad actor' is the definition.
'perpetrator' can be an answer for 'actor' (thesaurus). I'm not sure about the 'bad' bit.
'for every exercise heartless rat' is the wordplay.
I cannot really see how this works, but
'for' could be 'to' (eg both can mean 'in the opinion of') and 'to' is present in the answer.
'every' could be 'per' ('per' means 'for each' or 'for every') and 'per' is located in the answer.
'exercise' could be 'pe' (Physical Education) and 'pe' is located in the answer.
an anagram of 'rat' is 'tra' which is present in the answer.
A single letter 'r' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for perpetrator that I've seen before include "One carrying out (crime)" , "One who commits a bad action" , "One committing (a bad deed)" , "Culprit" , "Committer (of a crime)" .)