Cut, beaver, a bit flustered (10)
I believe the answer is:
abbreviate
'cut' is the definition.
('abbreviate' can be a synonym of 'cut')
'beaver a bit flustered' is the wordplay.
'flustered' is an anagram indicator.
'beaver'+'a'+'bit'='beaverabit'
'beaverabit' with letters rearranged gives 'ABBREVIATE'.
(Other definitions for abbreviate that I've seen before include "Shorten (a word)" , "Shorten (text)" .)