making a clear high pitch sound using the mouth as a way to show excitement about someone or something. Can be spelled out over text to illustrate the act of 'whistling' or used in sentences as a figure of speech.
Bill: "Ah fuck that was a sickkkk one, (whistles repetitively) you were fully in there".

Nickiboy: "Thanks dog, its firing out here today (whistles)".

Dill: "You whistle that chick last night".
Rickie: "Ya mate gave her a proper whistle after rinsing down at the pub all night"
by billyrinsenheim April 29, 2021
First entry is completely correct.

But to add some interesting info... The term 'whistle' is used a multitude of times throughout HBO's, 'The Wire'. Although it is never distinguished or addressed directly, it becomes apparent that the term 'whistle' really refers to ONLY a pistol, a semi-matic handgun.

David Simon's bestseller book and basically the father/catalyst of The Wire is 'Homicide'. Again the term 'whistle' is NOT explicitly defined) (Wether its only a pistol, or maybe a type of Mac/Tec or a shotgun) However the book does make it clear that 'whistle' is a term used in Baltimore. This isn't explained out right, but through stories, recorded conversations with citizens and the times when slang was recorded throughout the book, it becomes abundantly clear that the use of the term is authentic, meaning 'whistle' is actively used there.
>> "Yo we movin' out now, make sure you grab yo whistle!"

>>"Yo man, what if someone jumps out on us, rolls up on our corner?" "Nah its straight man. Check it, Got dat whistle layin over there..." (Points at a pistol sitting on top of a tire on a car, semi hidden between the wheel well and the tire, but close to the corner/stash)

>> "Nigga, either sound off wit dat whistle or tuck it, you be obvious as shit right now!"
by OttotheIII February 28, 2013
Whis·tle (wĭs′əl, hwĭs′-)

The unit of measurement for kratom dosage. A "whistle of kratom" or simply a "whistle" is a moderate dose of kratom that is equivalent to approximately 2.5-3 grams of powdered kratom. The slang is mainly used in the Midwest and West of the United States. The term has been said to originate from a technique of powdered kratom ingestion which aims at reducing the tasting of the powder. A whistle is a dose that makes for a successful ingestion of the drug using this technique without feeling the strong taste or smell of the kratom. Such an administration is "clean as a whistle", hence the name.
"Hey, have you ever tried the red vein strain?"
"Never, hand over a couple whistles of it"

"Man I got that nasty kratom taste on this one..."
"Dude, you did more than a whistle."

"David, have you been digging in my kratom?"
"No man, I mean I had like half a whistle earlier..."
by Omlax June 7, 2016
Something that one blows, making a one pitch note.
I am going to blow a whistle to make a one pitch note.
by ian fortson December 5, 2003
That move was so whistle!

Did you see that girl? Soooo whistle
by IKNOWALITTLEBIT August 28, 2009
n late 14C+the mouth, the throat (Cassel's Dictionary of Slang, 1988).
'Mama Stefano, gosh, super, must be boiling. Here, sport, wet your whistle,' he exclaimed, while he slopped down the brick steps with a glass of wine for her ... (John le Carré: The Honourable Schoolboy,2000,Coronet Books, p.42).
by Petyush March 27, 2005