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
10 more definitions
Top Definition
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 05, 2011
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 03, 2011
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 14, 2011
1.s. f., Ictiol., Brasil,
teleósteo water fish cutting tooth candy, characterized for an extreme voracity and that it can constitute a real danger in the rivers and lakes where lives, therefore demonstrates great predilecção for animals that bleed;

Brasilian black bird of Amazon;

woman of libertine habits.
(3) --> Her girl is a piranha!
by aamap August 27, 2006
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 11, 2006
A group of 3 bitches or more, unsatisfied with their sexual life, that go out to a restaurant and just wait for the waiter to make the slightest, simplest mistake to devour him alive. The members of the group consist of the bitchy piranha, the bitchiest piranha, and the nice piranha who is willing to let you live.
PS. any attempt to appeal the bitchy piranhas will result in a catastrophic event, so for your safety and the sake of your tips, try to appeal to the nice piranha only.
Damn! i have a group of piranhas on table 21 that is taking most of my time.
by Pinche_patillas October 19, 2010

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