Demolishing bar, a lord's dog (8)
I believe the answer is:
labrador
'dog' is the definition.
(I've seen this before)
'demolishing bar a lord's' is the wordplay.
'bar a lord' can be anagrammed to 'LABRADOR'.
However, I'm not sure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for labrador that I've seen before include "Canadian region and dog-breed" , "Canadian peninsula - dog" , "Breed of retriever" , "Canadian region and breed of dog" , "Spaniard who works" .)