Dart about (4)
I believe the answer is:
flit
'dart about' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for flit that I've seen before include "Do a runner" , "Travel lightly and quickly" , "Scurry lightly" , "Fly quickly (by moonlight?)" , "Move (like a moth)" .)