Adjective: The resulting mental state of mind after ingesting more than copious amounts of alcohol.

Generally prefaced with "God damn son." The phrase initially denoted how many beers it took to reach this stage, it has since expanded to any form of alcohol, and the number "15" no longer necessarily denotes how many drinks you've had, but has rather maintained its position in the phrase as a means of tradition rather than literalness.

One of the worst ages of being a teenager. You are in the middle and you wind up with the most problems that age. You are too young to drive without an adult, cannot go to the prom, and get a part time job like real teenagers. Your head is up your ass and one day you are still a kid watching cartoons and another day you'll like to have sex. This is also the age when most teen problems occur such as anorexia and cutting.

Is when you stick your feet in Burger King lettuce.

An age in a person's life when they aren't a kid, an adult or even a preteen but a teenager.

burger king foot lettuces

As seen on How I Met Your Mother, used in reference to your cards in a game of blackjack, but about the bang-ability rating of a girl. In blackjack, a player says "hit" if he wants another card. Trying not to go over 21, 15 can be a bad hand, because the blackjack player isn't sure if he wants to hit or not.

noun.

A '15' (pronounced 'quince' keen-seh) or a 'Quinceañera' is the milestone birthday party that Mexican girls and their families throw in honor of the big one-five. It symbolizes a girl becoming a woman.
And let's be honest, it's also an excuse to throw a huge ass party, because we Mexicans love throwing big parties.