Sound scared (4)
I believe the answer is:
gasp
'sound scared' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gasp that I've seen before include "Gaps in struggle for breath" , "Say "ah"" , "Struggle for breath with open mouth" , "Sudden intake of breath" , "Utter breathlessly" .)