Emphatically not at home! (3-3-3)
I believe the answer is:
out-and-out
'home' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for out-and-out that I've seen before include "Definitely" , "Utter, absolute" , "Thorough and complete - emphatically not indoors" , "In every respect" , "Utter and thorough - never in" .)