Its has been used by ronaldo to express his hapiness winnin ballon dor, and then he has bein usin it for any goal he scores,
U can also use it to express somethingepic
It is a Spanish word meaning yess often misspelt as 'suiii'. A famousplayer named Cristiano Ronaldo a
Portuguese footballer says this and has gotten very popular.
Friend 1: I got in Harvard.
Freind 2 (happy for him): Siuuuu!!