This is the 7992nd most frequent Korean word.
api
"Api" (아비) in Korean means "father" or "dad," but it is an old-fashioned or literary term rarely used in daily conversation.
Here, '아이' is used to refer to a child, indicating a young person.
이 아이는 정말 귀여워요.
This child is really cute.
In this usage, '아이디어' (idea) incorporates '아이' as part of the compound word, lending the notion of thought or concept.
그는 항상 새로운 아이디어를 생각해내요.
He always comes up with new ideas.
'아이구' is an exclamation in Korean expressing surprise or slight dismay.