SI

Abbreveation of Science and Industry, possibly the most popular Half-Life mod around.

'I'm sorry mum, i can't go and have a bath, im going to play SI'

'I'd rather play SI than CS'

by Anonymous June 26, 2003

si

when one is typing the word "is" really fast and without thinking.

i think he si very nice

by winnie foster November 16, 2017

SI

Means self insert. The character you use and identify yourself to have sex with your anime waifu.

-I'm going to write a fanfiction between my SI, Jackard Bigchub Maximus, and Sagiri-chan.
+Do it elsewhere. Disgusting.

by FancyDuck December 3, 2018

Si

When you have no idea what the fuck your Spanish teacher is talking about.

: ¿Más preguntas?
: Si
:¿Cuál es la pregunta?
:Si

by I got a 7 in Spanish ab June 11, 2020

SI

Sick Invite ( thank you for the non-invite )

You went for sushi!! SI (sick invite)

by 1-888 khod December 31, 2020

Si

the kinda deals that make you boogie

Si

by big bald obama September 30, 2021

SI

A shawty or girl

Wtw si🤔

by Urbanblackuser December 14, 2021