Eye-grabbing email subject line (6)

I believe the answer is:

urgent

(Other definitions for urgent that I've seen before include "Calling for immediate attention" , "Pressing, burning" , "Of immediate importance" , "Demanding immediate attention" , "Needing immediate attention, don't delay" .)

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.