Hairy beast shortly trembled, shorn by brute (5)
I believe the answer is:
yahoo
'brute' is the definition.
(I've seen this in another clue)
'hairy beast shortly trembled shorn' is the wordplay.
'hairy beast' becomes 'yak' (I've seen this in another clue).
'shortly' means to remove the last letter.
'trembled' becomes 'shook' (shake can mean to tremble).
'shorn' indicates the central letters (shorn of edges).
The central letters of 'shook' are 'hoo'.
'yak' with its last letter taken away is 'ya'.
'ya'+'hoo'='YAHOO'
'by' acts as a link.
(Other definitions for yahoo that I've seen before include "Brutish lout" , "Swift chap" , "Lout, boorish person" , "Lout (in Gulliver's Travels)" , "Boorish louts" .)