bite (off) more than (someone) can chew

Translations
взяться за непосильное дело
He bit off more than he could chew by taking on that project.
Он взялся за непосильное дело, взявшись за этот проект.
Definitions
To take on a task or responsibility that is too difficult or too much to handle; to attempt more than one is capable of managing.
Words
bite

verb
откусить
off

adverb
от
more

adverb
больше
than

conjunction
чем
someone

pronoun
кто-то
can

functional word
может
chew

verb
прожевать