A condition where someone can never look straight at you because one of their eyes is always pointing in another direction. Often giving the impression that the person is mentally retarded.
Wall-eyed Wally can only look at you with one eye at a time while the other eye points elsewhere...
A person with the inability to look directly in front of him/herself with either eye, rather each eye looks at its respective wall (i.e. left or right wall), thus walleyed.
Dude, stand directly in front of Carlos, he won't be able to see you he's fucking walleyed.