"Hey, I've got a secret . . ." (4)

I believe the answer is:

psst

(Other definitions for psst that I've seen before include "Whispered exclamation to attract attention" , "Sibilant interjection to call attention" , "Interjection to attract someone's attention without alerting others" , "Whispered attention grabber" , "Soft sound to get someone's attention" .)

I've seen this clue in The New York Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.