thief; comes from Arthur cartoon episode "World's Greatest Gleeper"
The word people say when having sex.
OH Jamal, stop..GLEEPER GLEEPER GLEEPER
square headed boy with small nipples.
look at that gleeper at the water fountain.
Subterranean mole-like ancient species that creates holes in the earth, and steal "gleep" people who fall down.
Look out, its a gleepers hole !!