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1.
Dates back to a 1850s lawyer in NYC using very ambiguous methods to obtain right in law suits. As his surname was something like Sheister a judge used "sheisty" as an adjective referring to methods that are immoral, impure, two-faced, opportunist, unreal, fake.
He's a sheisty guy. Don't use sheisty methods.
by arturelis October 18, 2004
 
2.
Shady or sneaky in nature. Usually describes a person.
A guy took coworkers money for movie tickets that turned out to be cheaper than he quoted and he did not mention it to his coworkers or refund the money... That's one sheisty asshole.
by Darci "Dirty-D" September 09, 2004
 
3.
Sheisty means someone is scandalous, stingy,does evil things and is two faced and is sneaky sneaky!
"Dude, did u know that Chad hid all his cards under the table when we were playing strip poker so he didn't have to get naked, how sheisty is that?"
by Amberface May 01, 2004
 
4.
A lying, cheating, scamming, two-faced, son of a bitch who smiles in your face while completely gypping you out of your money.
A mechanic who sells you a car for $5,000 that breaks down in less than a week of buying it and refuses to take it back and refund the money then jacks you around for 3.5 months about fixing the damn thing, doesn't; he manages to get it running but his sheisty ass lied about it being the battery - when it is really the engine - so now you can only sell it to Carmax for $1,200. That is a sheisty motherfucker.
by fuckedbymechanicwithoutlube July 03, 2009
 
5.
To be sheisty,to be a sheist:

To succeed sneakily with mallice
To venture covertley with intent for a personal gain in an subtle manner (sneeky manor)

ie. when your cat steals your spot on the couch he examplifies the true nature of a sheisty mother fucker
note: chanage the spelling and you are sheisty mother fucker
shut up eat a dick
by drunkards May 10, 2008
 
6.
A modern adjectival outgrowth the noun "shyster." The original term refers to someone who behaves in a disreputable or unethical fashion. Thus a "sheisty" person or behavior is one which appears overtly, even lewdly, unscrupulous.

The origin of "shyster" may be from the German "Scheißer" meaning pooper (MW) or from the old use of "shy" meaning disreputable (OED).
The guys at that party were completely sheisty.

You look really sheisty when you grease your chest.
by sheistamatic October 04, 2011
 
7.
Someone who is shady and not totally honest.
Jon told me he was going to his friends house tonight, but his car is not there. He is soo fucking sheisty.
by Brooke November 30, 2003