Absolute thug punches even if on his last legs (13)
I believe the answer is:
thoroughgoing
'absolute' is the definition.
(thesaurus)
'thug punches even if on his last legs' is the wordplay.
I cannot quite understand how this works, but
'thug' could be 'rough' (both can mean a violent person) and 'rough' is located in the answer.
'last' could be 'go' (synonyms) and 'go' is located in the answer.
'even if' could be 'tho' (I've seen this in another clue) and 'tho' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for thoroughgoing that I've seen before include "Complete, absolute" , "comprehensive" , "to the end" , "Extremely meticulous" .)