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3.
sei
a female girl.

also has lots of pink.
that sei is mad retarded
by Canin July 20, 2003
 
1.
Sei
To be incredibly epic at basically everything. Seems to be from a different dimension, though this is up for debate. Will not admit to having ninja skills even though said skills are witnessed regularly. Prone to anime-type reactions (aka loud and obvious), usually ending in some form of destruction.
Person 1: WTF happened in here!? All the desks and chairs are destroyed!!
Person 2: Someone pissed off (insert random name here).
Person: What an idiot, everyone knows (insert random name again) is a Sei.
by Kiri :D June 20, 2010
 
2.
A person who breaks the Sixth Commandment which signifies the person slept with a married person.
"Oh shit! He just pulled a Seis"

High five for scoring with a married chick man!
by Seis716 July 20, 2010