Boy accepts it's a weird dog (8)
I believe the answer is:
alsatian
'dog' is the definition.
(I know that Alsatian is a type of dog)
'boy accepts it's a weird' is the wordplay.
'boy' becomes 'alan' (I've seen this before).
'accepts' means one lot of letters goes inside another.
'weird' indicates anagramming the letters.
'its'+'a'='itsa'
'itsa' anagrammed gives 'sati'.
'alan' going around 'sati' is 'ALSATIAN'.
(Other definitions for alsatian that I've seen before include "Large dog and person from northern France" , "Large dog and someone from Alsace" , "Large canine, may be police dog" , "Large dog and someone from northern France" , "Dog (from French border region?)" .)