Sound surprised at new gaps (4)
I believe the answer is:
gasp
'sound surprised at' is the definition.
'gasp' can be an answer for 'sound' (I have seen 'Sound of astonishment' mean 'gasp' so perhaps 'sound' could also mean 'gasp'). I am not certain of the 'surprised at' bit.
'new gaps' is the wordplay.
'new' is an anagram indicator.
'gaps' is an anagram of 'GASP'.
Can you help me to learn more?
(Other definitions for gasp that I've seen before include "Sound of astonishment" , "Pant" , "Utter breathlessly" , "Struggle for breath with open mouth" , "Catch one's breath in astonishment" .)