Having a drab, dull, or unremarkable appearance, often used to describe hair color that is a light brown or grayish-brown. She had mousy hair that blended into the background, making her easy to overlook.
Timid, shy, or lacking in confidence, often used to describe a person's demeanor or behavior. Despite her mousy demeanor, she surprised everyone with her bold decision.
Infested with mice or characterized by the presence or smell of mice; mouse-like. After months of neglect, the pantry had become mousy, and we could hear scratching behind the walls.