A girl, usually attractive and promiscuous, that acts as if she knows nothing and sleeps around; A Dumb bitty is usually a slutty slop show. In some cases, The dumb bitty is truly, truly retarded.
"There is so much writing in this e-mail!"
" Just copy and paste it"
"I am too lazy"
"You dumb bitty"
"You spilt your drink on me, you dumb bitty!"