Actor with servant confining black dog (8)
I believe the answer is:
doberman
'dog' is the definition.
(breed of dog)
'actor with servant confining black' is the wordplay.
'actor with' becomes 'doer' (I can't justify this - if you can you should believe this answer much more).
'servant' becomes 'man' (man is a kind of servant).
'confining' means one lot of letters goes inside another.
'black' becomes 'b' (as in pencil classifications).
'doer'+'man'='doerman'
'doerman' going around 'b' is 'DOBERMAN'.
Can you help me to learn more?
(Other definitions for doberman that I've seen before include "Long-legged terrier" , "Originally German breed of watchdog" , "...pinscher, large dog" , "Dog used as guard - bond mare (anag)" , "Barker" .)