Short erect tail (4)
I believe the answer is:
scut
'short erect tail' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for scut that I've seen before include "Small tail as of rabbit" , "Cuts into a small tail" , "Deer's tail" , "Reindeer's tail" , "Short tail, such as rabbit's" .)