Def. 1: Used to describe something particularly easy, generally a task.
Def.2: Used to describe someone of the opposite
sex, particularly in how easy it
will be to pick that person up. A sure thing.
origin: beginner's little league game of the same name, where the degree of difficulty in hitting a
baseball is reduced by placing it on a tee for the child to hit.
"I know the guy who runs that place, so getting our
friends in should be teeball tonight."
"See that
drunk chick over there? Total teeball."