어따 대고
an example straight from naver

어따 대고 말대꾸하고 화풀이를 하는 거야?

it looks like 어따 is short for 어디다 but i am not too sure of its usage even after reading thru its definition.

what is the exact meaning of 대고? usually 대다 means "face with" or "in close contact" but pairing with 어따 does not seem to take on those meanings at all.

Question

어따 대고
an example straight from naver

어따 대고 말대꾸하고 화풀이를 하는 거야?

it looks like 어따 is short for 어디다 but i am not too sure of its usage even after reading thru its definition.

what is the exact meaning of 대고? usually 대다 means "face with" or "in close contact" but pairing with 어따 does not seem to take on those meanings at all.

Answer

어따 is wrong spelling of 얻다
얻다 is contraction form of 어디에다(가)
어디에다(가) is emphasizing expression of 어디에

~에 대다 :  어떤 것을 목표로 삼거나 향하다.	toward something
e.g.
하늘에 대고 하소연을 했다. 
아이들이 나무에 대고 돌을 던지고 있다. 
어머니는 아들에게 대고 그동안의 불만을 한꺼번에 내쏟았다.

얻다 대고 = 어디에다 대고 = 어디를 향해 toward which place, whither

얻다 대고 말대꾸하고 화풀이를 하는 거야?
Where are you talking back and venting your anger?
= To whom are you talking back and venting your anger?
= How dare are you talking back and venting your anger on me?