Cry of fear (3)
I believe the answer is:
eek
'cry of fear' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eek that I've seen before include "Alarmed expression" , "Expression of mild fright" , "Expression of surprise" , "fearful cry" , "Yikes! Oo-er!" .)