Close up Oscar sees audience's dirty (7)
I believe the answer is:
occlude
'close up' is the definition.
(thesaurus)
'oscar sees audience's dirty' is the wordplay.
I cannot really understand how this works, but
'oscar' could be 'o' (phonetic alphabet: alpha, bravo, charlie etc.) and 'o' is present in the answer.
'sees' could be 'cc' (more than one C or see) and 'cc' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for occlude that I've seen before include "cover" , "Close up (an orifice or passage)" , "Stop up, obstruct" , "Cut or shut off" , "Shut out, obscure" .)