Outstanding passage from theremin entertains (7)
I believe the answer is:
eminent
'outstanding' is the definition.
(eminent can mean esteemed or outstanding)
'passage from theremin entertains' is the wordplay.
'passage from' indicates the answer is hidden within the clue (a sequence or passage of letters from the clue).
'EMINENT' can be found hidden inside 'theremin entertains'.
(Other definitions for eminent that I've seen before include "Distinguished and admired" , "Famous and respected" , "Lofty; famous" , "Exalted in rank" , "Distinguished, prominent" .)