Criticise rubbish specifically included (5)
I believe the answer is:
roast
'criticise' is the definition.
(I've seen this before)
'rubbish specifically included' is the wordplay.
'rubbish' becomes 'rot' (both can mean nonsense).
'specifically' becomes 'as' (I am not sure about this - if you are sure you should believe this answer much more).
'included' means one lot of letters goes inside another.
'rot' going around 'as' is 'ROAST'.
Can you help me to learn more?
(Other definitions for roast that I've seen before include "pan" , "Cook with dry heat" , "Carpet" , "Heavily criticise" , "Swelter" .)