Interrogation (5,6)
'interrogation' is the definition.
(third degree is a kind of interrogation)
This is the entire clue.
(Other definitions for third degree that I've seen before include "Demanding viva" , "kind of burns" , "Demanding quiz" , "What you may study for after master's" , "doctorate, possibly?" .)
'interrogation' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for grilling that I've seen before include "Cooking by direct exposure to radiant heat" , "Severe questioning - in oven?" .)