The greatest word. Ever. Used when there's absolutely nothing else to say, between words, and as a root word. Misled people also believe it's what cow's say, but there's is more like, "MUWOOERRROO."
"...
...
...
MOO!!"
"Moo. I got a new car today, moo, it's BLUE!! Which ryhmes with MOO!!"
a strike up word. usally used on aim by guys who are too scared to talk to the girl they like or incredibly hyper people. also a great word to use if someones talking toyou and you dont want them to.
john: moo
Jane: wtf?
john: idn wat^
jane:nmu
John: cool ... so on and so forth till the girl realizes wats happened and thn has to leave all of a sudden
Kyle: hey
jon: moo
kyle: wat
jon: moo
kyle: ok i g2g fag