This is the 553rd most frequent Korean word.
자기
"자기" means "oneself" or "honey/sweetheart" (informal term of endearment).
In this sentence, '자기' refers to the subject themselves, used to emphasize that the action was performed by the individual being spoken about.
자기가 직접 준비했다.
They prepared it themselves.
Here, '자기' is used as an affectionate term often between couples, translated as 'honey' or 'darling' in English.
자기야, 여기 봐!
Honey, look here!
In this example, '자기' is used to refer to the listener conversationally, making the tone familiar or intimate.