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1.
HBM
Hyper Bitch Mode
A synonym for PMS, premenstrual syndrome.
Guy 1: hey whats up?
Girl: blah blah blah fuck you!
Guy 1: what did i do?
Guy 2: don't worry about it man, she's just in HBM.
Guy 1: oh, alright then.
by Santhony January 02, 2010
 
2.
HBM
birthday of the chick who birthed you; HAPPY BIRTHDAY MOM
EXAMPLE
kid: it would be pretty cool if i put an entry on urban dictionary for my mom
mom:thats so sweet! thank you!
grandma that was told to read this: NICK! WHAT DOES PAULING MEAN! I DON'T KNOW WHAT A NUTSACK IS! IT DOSEN'T MAKE SENSE! HOW DO YOU SPELL HBM! WHY CAN'T THE DOG EAT IT!
by friartuck November 22, 2010
 
3.
HBM
Heterosexual Bar Male

The type of male that is stereotypically found in a bar where grinding, drinking, surrounding girls, and attempting to pick up, are the focus.

They are also prone to fights and obnoxious yelling.

Men who fall into this category are inexplicably identifiable outside of the bar in broad daylight.
"There are too many HBMs in this bar, I want to get out of here."
by Chris Dehaan March 11, 2009
 
4.
HBM
Head bob movement. The bobbing of ones head when they approve of something, usually with a smile. Most often used over an instant messenger service.
Guy: Dude, I just got a new car!
Guy 2: HBM, thats sweet.
by IXI BLITZ IXI October 21, 2010
 
5.
HBM
An acronym standing for "Hard Body Mafia," which is quite possibly the best Xbox Live gang on "Saints Row 2." You will know when you see us because we tend to wear all-blue clothing. When you see a gang of all-blue, that means you better tuck your head between your legs and run like a bitch because you're about to get pwned with shotties, AK's, and rocket launchers.
"Saints Row 2" Newb: "Oh shit! Who is that gang on the rival team all decked out in blue?!"
"Saints Row 2" Vet: "That'd be HBM...one of the baddest mothafucking gangs on here! You better get outta here newb!"
by B_Rox2LP_90 March 30, 2009