Expression: To weasel out of

A weasel is a "small slender active carnivorous mammal that is able to prey on animals (as rabbits) larger than itself. They are mostly brown with white markings, and in northern forms turn white in winter."

We also use the word weasel to mean "a sneaky, untrustworthy, or insincere person."

So, to weasel out of something is to escape it or evade it. The idea here is that you said you would do something, and now you don't want to, so you look for a way to weasel out of it. Here are a few examples:

I promised to help Arthur move, but I'm so tired I'm going to try to weasel out of it.

Eames was always very good at weaseling out of things, and nobody every got angry with him.

If you commit to this, don't try to weasel out of it later, OK?


Note: the quoted definitions above are adapted from the Merriam-Webster Dictionary.