Singer not entirely conscious in a trance (7)
I believe the answer is:
sinatra
'singer' is the definition.
(Frank Sinatra)
'not entirely conscious in a trance' is the wordplay.
'not entirely' says the answer is hidden in the clue.
'SINATRA' can be found hidden inside 'conscious in a trance'.
(Other definitions for sinatra that I've seen before include "Francis Albert, late lamented crooner" , "Frank -, twentieth century US singer" , "Was his singing a strain?" , "Francis Albert ..., singer and actor" , "Francis Albert, 1915-1998" .)