Learn Hardcore Korean: bae-uga mudaeeseo janeun cheokhaesseo. - The actor pretended to sleep on the stage.

Breakdown of bae-uga mudaeeseo janeun cheokhaesseo.

What does -는 척하다 mean in this sentence?

-는 척하다 means to pretend to do something or to act as if one is doing something.

So:

In this sentence, 자는 척했어 means the person pretended to be sleeping.

This pattern is very common with action verbs:

Why is it 자는 척했어, not just 자다 척했어?

Because 척하다 needs the verb in a modifier form before it.

With action verbs, the usual pattern is:

So:

You cannot normally put the dictionary form directly before 척하다, so 자다 척했어 is not grammatical.

Why is the verb before 척하다 in the -는 form, even though the whole sentence is in the past?