If you're stooped, you're hunched or bent over. An elderly woman leaning over a walker might be described as stooped.
Very old people and those with curved, bent shoulders and backs are stooped. A witch in a fairy tale might be described as stooped, or an injured football player who staggers, stooped over with pain, off the field. The verb stoop comes from an Old English word, stupian, "to bow or bend," from a Germanic root. You might also hear a stooped person described as stoop shouldered.