bite off more than one can chew

(verb) to begin a commitment that you cannot finish

Example Sentences:

Timmy took too much food at the all-you-can-eat buffet, and now he feels sick. Timmy always bites off more than he can chew.

A: How is Engineering school?
B: I feel like I’m biting off more than I can chew. I don’t think I’m smart enough to study Engineering.
A: Nonsense!

Our boss bit off more than she can chew when she promised the client we’d have the project ready by next week. It requires at least two weeks!

Media:

Similar idioms:

1. chew over
2. catch on
3. chew one’s ear off
4. ace a test
5. chew someone out
6. knuckle down