(으)ㄴ 척하다 [Intermediate Grammar]

- (으)ㄴ 척하다

→ If an incomplete noun '적' meaning 'fake behavior' is used after a modifier of a verb or an adjective '-(으)ㄴ/는,' it indicates that a subject does a spurious behavior or an action, unlike the truth. '체하다' can be used the same as '척하다.' 

Similar grammar >>>>  A/V - (으)ㄴ/는 양

Example: 

1. 그 사람은 다른 사람들 앞에서 언제나 똑똑한 척해요.
    He pretends to be smart in front of others.

2. 잘 모르면 아는 체하지 말고 언제든지 물어 보세요.
    Don't pretend to know about it and just ask me whenever you need anything.

3. 텔레비전을 볼 때 엄마가 심부름 시키는 소리를 듣고도 못 들은 척했어요. 

    When I watched TV, I pretended not to hear my mother asking me to run an errand.

4. 무서워서 자는 척했어요. I pretended to be asleep because I was scared.

5. 남자 친구가 있는 척해요. Pretend she has a boyfriend.

6. 귀찮아서 바쁜 척했어요. I pretended to be busy because I was bothered.