a person who is regarded as treacherous or sneaky
"Don't listen to his excuses; he's just trying to weasel his way out of paying for the damages."
small carnivorous mammal with short legs and elongated body and neck
"The weasel darted through the tall grass, its sleek body gliding silently as it hunted for mice."
The least weasel, Mustela nivalis.
"The farmer pointed to the tiny gray fur on his porch and said he must have caught a weasel last night."
To achieve by clever or devious means.
"He weaseled his way into a corner office without ever doing any actual work."
The word "weasel" comes from Old English and originally referred to the animal itself. A related verb meaning to act with cunning was added around 1900, inspired by the creature's reputation for sly behavior.