Roast beef out of this world (6)
I believe the answer is:
carpet
'roast' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'beef out of this world' is the wordplay.
'beef' becomes 'carp' (I've seen this before).
'out of' means to remove the last letter (I've seen 'out' mean this).
'this world' becomes 'pet' (I can't justify this - if you can you should give a lot more credence to this answer).
'carp' with its final letter taken away is 'car'.
'car'+'pet'='CARPET'
Can you help me to learn more?
(Other definitions for carpet that I've seen before include "It could be flying" , "Heavy fabric for floors" , "Roll the red one out for VIP" , "What may deaden sound in room" , "that probably won't be seen on the factory floor?" .)