Dope Tony's knocked out on, abrasive basic stuff (5-6)
I believe the answer is:
nitty-gritty
'stuff' is the definition.
(thesaurus)
'dope tony's knocked out on abrasive basic' is the wordplay.
'dope' becomes 'nit' (both can mean a stupid person).
'knocked out' suggests deleting specific letters.
'abrasive basic' becomes 'gritty' (I can't explain this - if you can you should believe this answer much more).
'tony' with 'on' taken away is 'ty'.
'nit'+'ty'+'gritty'='NITTY-GRITTY'
Can you help me to learn more?
(Other definitions for nitty-gritty that I've seen before include "Most important details (of a matter)" , "Essential details of a matter" , "Essential aspects" , "Brass tacks" , "Essence" .)