A Brazilian depreciating word that means bitch, whore, harlot... Whatever It's just a bitch trying to get your man. Keep your eyes on her ¬.¬
Aquela piranha tá tentando roubar o meu homem.
(That bitch it's trying to get my man)
by B_B_P June 22, 2015
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noun: Any wrestling or grappling technique (esp from Brazilian Jiu-Jitsu) that presses a body part or the ground against your mouth - sometimes yielding imprints of your teeth on the inside of your lips/gums or teeth marks on your opponents arms/legs.
No piranha moves today - I forgot my mouth guard!
by Yet another victim July 15, 2011
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A woman that fights or grapples (especially a practitioner of Brazilian Jiu-Jitsu) that is known for being very fast and vicious.
She's a really sweet girl until we get in the octagon - then she becomes a piranha!
by JennySea August 5, 2011
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adj: A determined, sneaky and fast opponent that is very hard to get rid of once they acquire their target.
That guy's a piranha if you have to fight him - he'll beat you down no matter how long it takes.
by Bill Just Bill July 3, 2011
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In internet usage, particularly forum message boards, a user who swarms a post with useless commentary. Not considered a spam, as the user will usually post as part of a larger group of users, and the said user will usually think their comment is complimentary or in some way helpful, even though it is not.

The comment is:
1) Usually worthless. "OMG, that's great!" is not as complimentary as they poster believes it to be, and only serves to waste the time of the original poster.

2) Not well thought out. The comment is usually quick, and does not justify itself. No reason is given as to why the user feels the way he / she does about said topic, image, story, etc.

3) Part of a mob mentality. Piranhas don't work alone, unlike most spammers. Their posts are usually followed by a swarm of like-minded posts, fueling the useless flood of empty comments.

NOTE: These types of comments are usually most prevelant on a forum centered around skills development. (Art sites, writing boards, game modification boards, etc.) Where a person skilled in whatever the forum centers on is easily attacked by piranhas and his / her post is quickly devoured.
Original Poster: "Hey Guys, I just finished this 1200 DPI artwork, can you give some honest critique so I can improve myself?"

Piranha3083: "OMG! You are my favorite person ever! 111! Have my baby!"

Piranhaman111: "Doood! You have mad skillz! OMFG! 1337!

Prinininsenhna: "ROFLES. SO GOOOOD! I LOVE IT!"

Original Poster: "That doesn't help me at all, that was completely pointless!"

Piranha: "OMG!"

by Kyle Hinton March 12, 2006
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A voracious, predatory, highly competitive, ruthless, alpha male/female.
Often misspelt Pirhana
From the 'Apprentice'. One contestant observing the fish swimming at the London Aquarium, mused to a finalist'They're piranhas? But they look so friendly' You haven't seen their teeth' the finalist replies wearily. After 12 weeks in pursuit of the coveted job,he was covered in the nasty bite marks of his fellow contestants.
by Henley June 14, 2007
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