Siu 

A celebratory expression often used by Cristiano Ronaldo after scoring.

SIIIUUUUUUU.

Siu

“That food was banging love”….. SIIIIUUUUU

Siu by Brown dog December 12, 2021

SIU 

SIU = Southern Illinois University, located in Carbondale, Illinois. Home of the Salukis!

SIU basketball dominates the Missouri Valley.

SIU is one of the top party schools in the nation.

SIU by Grey Dawg November 5, 2009

SIU 

An acronym for "suck it up"

Person 1: Ow, I bumped into that wall.
Person 2: Man, SIU go beast it

SIU by Lynbrook Viking April 4, 2006

SIU 

Acronym for Special Investigation Unit for law enforcement/prosecutors and insurance compaines

When that boatload of coal claimed whiplash, they called SIU in to videotape them playing basketball

SIU by Teabag April 24, 2006

SIU 

Acronym for 'step it up' meaning for one to reach a new/higher level then previously on.

Commonly used in forums and online gaming.

Guy 1: Dude, your bottom of the team. SIU

Guy 2: Hey, I'm new, I'm trying my best okay!

SIU by Charlag November 14, 2011

Siu 

A trademark goal celebration by football player Cristiano Ronaldo.

It was first seen when celebrating scoring a goal for Real Madrid and has since become a trademark move even after moving to another club.
After scoring the goal Ronaldo ran, performed a mid-air pirouette, planted his feet and yelled a guttural "Siu!".

The spelling of the phrase is not widely agreed upon, but it equates to "Si" which means "Yes" in Portuguese.

The scream? The players know I always do that shout when I score a goal or when we win"

"It’s our shout, from Real Madrid."

-Ronaldo regarding "Siu" on Spanish TV station Cuatro after the 2014 Ballon d'Or ceremony.

Siu by onenemesis January 22, 2022

SIU 

A word the world of football/soccer use all the time. It is known by a player called Cristiano Ronaldo that makes that sound whilst doing his celebration after scoring a goal.

Ronaldo: SIUUU
Fans: SIUUUU

SIU by Definition Merchant January 23, 2022