Buzzing with activity (5)
I believe the answer is:
astir
'buzzing with activity' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for astir that I've seen before include "Up and about -- is art (anag)" , "Out of bed or on the move" , "This isn't still" , "In motion - out of bed" , "Excited; out of bed" .)