In Cantonese, it can mean:
iii. close friend
ii. You're such a fucking sohai lah! Don't you know how to eat a pussy?
iii. Hey sohai! Long time no see!
If word is separated,it would mean: so(crazy) hai(cunt,pussy,vagina)
Crazy/Fucking Crazy/Crazy shit
It means a fucking crazy person,fucking stupid person,fucking jackass person,fucking asshole person,etc.
It can be used to scold somebody,a nerd,or an enemy,even friends.
-That Sohai is gonna get whacked in the face.
-You're a stupid sohai.
-You're damn Sohai.
-Look at that Sohai,duno(don't know) how to use a spoon.
-You're a Sohai you know that,trying to attempt a jump down from that 5-storey building.