Easily frightened (5)
I believe the answer is:
timid
'easily frightened' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for timid that I've seen before include "Diffident, faint-hearted" , "Gutless" , "Easily frightened" , "Nervous and easily alarmed" , "Pusillanimous" .)