SI

Short for Survival Instinct - the ability to know what to do to stay alive.

His SI stopped him from committing suicide.

si

si deez nutz

person one: how do you say yes in spanish
person two: si-
person one: SI DEEZ NUTS U STOOPID

Si

Is an abbreviation for Stupid Idiot, not to be confused with a nickname for someone called Simon.

You fucking Si; get 'ere now you Si

Si

the kinda deals that make you boogie

Si

SI

Sick Invite ( thank you for the non-invite )

You went for sushi!! SI (sick invite)

SI

In fanfiction, an acronym for self insert

He wrote a Pokémon SI story

Si

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

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