Scribble idly (6)
I believe the answer is:
doodle
'scribble idly' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for doodle that I've seen before include "Scribble aimlessly or absent-mindedly" , "Casual drawing" , "Scribbled drawing" , "Absent-minded scribble" , "Absent-minded drawing" .)