A weasel is a small animal with brown fur, but weasel is also used to describe a person you cannot trust weasel out of something.

Our work trip is coming up next week.

Oh, I'm actually not going.

What?

But the boss said, Everyone has to go.

How did you weasel out of it?

I told the boss that my 102 year old great aunt is coming to town that weekend.

If you weasel out of something, you avoid doing something, usually by lying or persuading someone in a clever way.

The word weasel acts like a verb.

In this expression, Jonathan probably weaseled out of going on the work trip by lying to his boss, and that's English in a minute.