The two words that are used when a nine year old gets salty
Fortnite nine year old: "Fortnite is best!!1!!111111!
Sensible Person:"No it aint"
Salty nine year old "Ur mom"
something very cringy you can call other people if you don't give a shit about what they're saying.
person 1: yo bro I found this girl I really like!
person 2: ur mom
"Ur mom is so fat that one picture of her filled up the whole phone storage"
Ur Mom means that you had sex with their mom leaving them concerned and confused.
Them:What were you doing last night.
YOU:Ur MoM
THEM:what the !@$#!