This is the 19188th most frequent Korean word.
안니카
"안니카" is not a standard Korean word; it may be a transliteration of the name Annika.
Here '안니카' is used as a proper noun referring to a person's name.
안니카는 학교에서 공부합니다.
Annika studies at school.
In this sentence, '안니카' is again used as a proper noun, indicating a person with a level of familiarity.
저는 안니카와 친한 친구입니다.
I am close friends with Annika.
Here '안니카' is used possessively to attribute an opinion to the person named Annika.