Easy clue (5)
I believe the answer is:
light
This clue is a double definition.
'easy' is the first definition.
(I know that easy can be written as light)
'clue' is the second definition.
(Other definitions for light that I've seen before include "Pre-eminent person; window" , "Mild" , "Pane of glass" , "Match - agile - easily digested" , "Low in density" .)