noun
weasel
WEE-zuhl/ˈwiːzl/
A small meat-eating mammal with a long, slender body and short legs.
The weasel darts toward a mouse.

Etymology
Old English weosule already named the animal. Its deeper origin is obscure, though Watkins suggests a probable relationship with the name bison through a shared reference to a foul, musky smell.
In context
The weasel is a common garden resident. But it's fast and elusive, so rarely seen. This one has spotted a mouse.