Cancels pet's treatment - having Alsatian's tail docked for show (9)
I believe the answer is:
spectacle
'for show' is the definition.
(I've seen this before)
'cancels pet's treatment having alsatian's tail docked' is the wordplay.
I cannot really see how this works, but
'treatment' could be 'ect' (ECT is an example) and 'ect' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for spectacle that I've seen before include "Visually striking performance or display" , "Wonder" , "marvel" , "presentation" , "Showy pageant" .)