Twerpy Mouse
n. slang 1. A playful term used to describe a small framed female who often does not think before acting, but instead, and most often, acts and reacts on pure impulse without rhyme or reason.
(as she walks directly into a bedroom wall that has been there for years,) "Robin... That wall has been there for years. Why did you just walk into it? You're such a twerpy mouse."