Frustration indicator (4)

I believe the answer is:

sigh

(Other definitions for sigh that I've seen before include "Sad exhalation" , "Exhale wearily" , "Weary sound" , "Moan softly" , "Sound of regret" .)

I've seen this clue in The Wall Street Journal.

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.