1) To look at someone from the side to give them a glare or look of disapproval, like a rabbit. As a rabbit usually has a small eyes, located on the side of its head and typically has an air of superiority.
The hairy eyeball is the death stare.
Its the look somone gets when theyre hearing a bunch of bull, or they are glaring at their worst enemy, parent, great aunt-gladdie, teacher, employer, stalker, neighborhood arsonist-pedaphile-rapist, nosey neighbor, siblings, that 13 year old and her friends following you around the mall because your so attractive.
Larry caught a glimpse of Judy, his most recent ex, with a horrible look in her eyes; she was giving him the hairy-eyeball.