A female version of the broski, or a more intense version of the bra.
A broskaya is the best female friend one could have.
Broskaya levels can be reached with both fellow broskayas and broskis, but it is more common in female groups.
A broskaya is the friend who blurts out your most embarrassing secret, gives you purposely bad advice for the school play and borrows your favorite shade of lipstick when your date is tomorrow.
Broskayas are not frenemies, however. They always prove to make your life better with their utter humiliation of you. For example, the date your broskaya prevented? Your date was a registered sex offender. The secret your broskaya blurted? Your crush now admires your dedication to teddy bears. The school play? You got really bad acne on the day of the performance.
Broskayas also handy for holding your perm while you vomit, and no-strings-attached lesbian experimentation. Now, don't you wish you had one?
"Broskaya! Can you do me a favor and try this? I want to be sure it's not poisoned."
"My broskayas and I egged their house."