"나쁜 아이가 인사를 안했어요."

Translation: The bad child did not say hello.

[yipivan]

Alright to have no space between 안 and 했어요?

[KamiraAkari]

I've seen a lot of natives do it, so I think it is

[puptarts]

I said "The bad child did not say hi" and got it wrong. Reported Sunday 10 Dec 2017.

[BryanH6]

Its more like "introduce himself".

[crimsonNabi86]

"the bad child did not greet" is also wrong? does it sound unnatural? (not a native english speaker)

[oee16]

"to greet" is always used with object. E.g.

I greet her- I, subject; "her", object.