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1.
Short term for Psycho

People who can't spell Psycho say syco.
Person who can't spell psycho : Yo dis syco caem up to mi nd sht mi in da fec fr splln so bdly.

Me : Good, but obviously you haven't learnt your lesson.
by darkmyst August 29, 2005
 
2.
The word "Syco" originates from Japan where it implies something is awesome. In a similar way the words Fully Sick is used. This word does not have the same meaning as the word Psycho! as stated by darkmyst. The word psycho describes the mental illness or psychosis
That Dude is going Syco on that Skateboard.
by The Syco Arbitrator January 31, 2010
 
3.
The best shag i've had!!!
One gorgeous guy that i'd do over and over again!!!
Jane - 'Don't tell me you did it again?'
Sarah - 'Who can blame me Syco's just the best!'
by unknownbiatch March 13, 2005