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1.
A doctor of questionable ablitiy and reputation.
Even tho Erin's dad claims to be a doctor, I say he's a quack! He didn't even graduate high school!
by Stella Lafayette December 04, 2004
508 115
 
2.
The sound a duck makes
"Quack"
by Lindsay February 25, 2003
421 138
 
3.

1. a fraudulent physician

2. any physician
This quack has no skills in medicine at all.
by Light Joker December 31, 2005
187 114
 
4.
A very sexy sound when moaned by a girl.
guy: so what do ducks say?
girl: ...quack.....
by MallardDuck January 31, 2009
152 112
 
5.
noun: slang for "crazy" common in the south, especially near areas of high duck concentration.

1. That's quack, man.

2. You're so quack.

3. Dude! that's quack, yo!
by thats whack February 22, 2009
92 65
 
6.
A scam-artist. A person who makes up bullshit medical products or advice or prescriptions that don't work. A snake oil salesman.
Most alternative medicine "specialists" and psychics are quacks.
by Anonymous February 17, 2003
98 73
 
7.
-To quack is to perform an act that displays one's stupidity, incoherence, lack of coordination, or outright inability to relate or adapt in a social setting. Derived from the sound a duck makes, more specifically the verb form for what a duck (see definitions 5,8, and 9 for "duck") does.
-To fuck up the situation for everybody.
You missed the biggest quack!
What happened?
____ ran down the hill, tripped and busted ass all over the sidewalk and fence by the tennis courts!

How was your birthday?
Fun as shit, we got fucked up then ______ quacked ridiculously by hitting the blunt BACKWARDS! He didn't even notice for like 2 seconds, then he got up and slid down the hill and lost his keys.
What a fuckin' quack

I dropped the entire pizza on the ground.
You're so quackin.
by DaQuackyPaki December 06, 2009
40 27