Knock over material in the studio - it's heartless and thoughtless (8)
I believe the answer is:
flippant
'thoughtless' is the definition.
(thesaurus)
'knock over material in the studio it's heartless' is the wordplay.
I cannot quite see how this works, but
'knock' could be 'pan' (both can mean to criticise) and 'pan' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
The remaining letters 'flip' 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).
'and' acts as a link.
Can you help me to learn more?
(Other definitions for flippant that I've seen before include "Not showing proper seriousness, disrespectful" , "anything but serious" , "Showing disrespectful levity" , "light" , "Irreverent, saucy" .)