It is the short of "don't know", popular used by lazy people or who dislike typing so many words.
I duno.
= I don't know.

I duno hu is it.
=I don't know who is it.
by Jaspon December 10, 2006
Very smart person , a beautiful face , and n very funny personality ... Remember a very very sexy guy .
That Duno is a sexy basterd .
by a very sexy lady . August 15, 2019
Term used when a person who have jumpstatted before is avoiding school.
Mog: im bout to duno challenge, fuck math exam

Borys: mog what happened to you :/
by nornica123 September 22, 2020
something you say when u dont know something or have nuthin to say
1)wat r u doin? (ur not doin anything) i dunoo
2)who do u like? (the girl/guy that everyone likes as always duh!) i dunooo
by adamchu May 12, 2004