Opera singer? Not entirely (5)
I believe the answer is:
tenor
'opera singer?' is the definition.
(thesaurus)
'not entirely' is the wordplay.
I cannot quite understand how this works, but
'not' could be 'no' (I've seen this in other clues) and 'no' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tenor that I've seen before include "direction" , "Pavarotti, for example" , "intent" , "Male voice (one of three?)" , "Eg, Placido Domingo" .)