1. Spanish for "yes."
2. Misspelling of "is."
1. "I suck." "Si."
2. "NO YUO FAGOT A COMPUTAR SI NOT A HAT!"
by Dj gs68 September 23, 2003
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Snickering in Silence
new for LOL because it applies much more than LOL when texting/typing and trying to be quite
While texting in class i received a message with a prime time to say "thats what she said" and/or "reminds me of my saturday night" or even "I get that all the time" so I sis'd vs lol'ing

"idk what happened it just went everywhere after i touched it"
sis
"reminds me of my saturday night"
by kevin "k-bone" December 26, 2009
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SiS as in Shit Its Sunday Commonly used on sites like Facebook and Myspace
John: Aw man SiS
Kevin: Dude I know
by Kife1100 April 5, 2009
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SI is the abbr. of stupid idiot , although it can also be used in a way in which it means mug
I.E. billy you fucking si, si does not mean sigh which means you bore.
by jake lowe February 11, 2008
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Smirk in Silence:
The act of putting on a straight face after putting someone in a spot.
Pulling someone's leg as a group where everyone acts normal in a scenario that is funny.
Used on social networks, chat rooms and forums..at least could be!
Totally loved getting on Spook's nerves acting as if I don't know him at the bar last night. Pulled a SIS.
by far_c November 2, 2009
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