She is a huge, fat, overweight librarian who has Caucasian skin, with short brown hair and wears a green long-sleeved dress. Like Mammy Two-Shoes before her, her face and head is never seen and is only shown from below the neck, though her head is briefly shown in one scene when Tom ties a bunch of books around the sides of her head as makeshift earmuffs.
She has a nearly bass-boosted voice and is cranky, irritable, obnoxious, and short-tempered, as she shakes the floor with her jumping as she screams. She does not like her nap to be disturbed. She is very noise-sensitive (ala Joe Bear from Tex Avery's "Rock-a-Bye Bear"), as she cannot stand any noise and gets cranky when disturbed even with the slightest noise as a pin drop.
Much like Tom's other notorious owner, she has severe temper problems and often aggressively blames Tom for all the chaos Jerry causes without doing any proper research. She even goes so far as to punish Tom in a brutal way by kicking him out to Mars when her sleep gets disturbed way too many times in the ending.
She is also shown to be a hypocrite as well, as she tolerates with the baby's crying, but not any of the noise that Tom makes. She is also hypocritical of calling Tom "lard belly" (after he swallows a drum whole) despite her appearance.