Look sound? (4)
I believe the answer is:
peep
I believe this clue is a double definition.
'look' is the first definition.
(peep can mean to look at something)
'sound?' is the second definition.
(I know that peep is a type of cry)
(Other definitions for peep that I've seen before include "Look furtively (either way)" , "Look furtively (in both directions)" , "Palindromic glimpse" , "Look furtively or voyeuristically" , "Look quickly" .)