A sound in one's ears or actually in the brain sometimes made by a disease called Tinnitus. Missed deadlines can make the same sound.
"I love deadlines. I love the whooshing sound they make as they fly by."
Douglas Adams, English novelist
Ooopss, I am late with my tax forms, just heard the deadline whooshing.
Usually preceded by "you are the", a title of praise for someone who has done something extraordinary. Functions identically to a host of other congratulatory expressions, such as "you kick ass," "you're the Man," "You're a champ," etc.