Somebody really unusual and/or makes you cringe.
"yo dude know that weird kid there? he stalks one of those hot girls."
A not normal noun or pronoun. weird is a way that something is doing what it's supposed to do not normally.
guy 1: hi...... nothing to see here.
guy 2: you're acting weird!
guy 3: yeah!
guy 1: what?! no, how?!
guy 3: you're saying weird things.
guy 1: like what?
guy 2, who interrupted guy 3: like nothing to see here.
When you don't know what this word means.
Weirdo: What does weird mean?
Some dude: someone that doesn't know the definition of that word