Peacock show? (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
tail
(Other definitions for tail that I've seen before include "Elongated appendage of an animal" , "Animal's elongated appendage" , "Comet's luminous trail" , "Follow - rear part of aeroplane" , "Follow furtively like private detective" .)