Call for attention (4)
'call for attention' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for psst that I've seen before include "Sibilant whisper to attract attention" , "Sibilant interjection to call attention" , "Interjection to draw attention" , "Sibilant sound made to attract attention" , "Sound of call to hear a secret" .)
'call for attention' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ahem that I've seen before include "Polite noise to draw attention" , "I say!" , "Throat clearing sound to catch attention" , "attention-seeker?" , "Interjection" .)