i-adjective
Most commonly describes a close, friendly, or familiar relationship between people. Often used in patterns such as 親しい友人, 親しい間柄, and 〜と親しい.
彼とは学生時代から親しい。
I have been close to him since our student days.
親しい友
I invited only close friends to dinner.
i-adjective
familiar; well-known to one
Used when a story, tune, place, topic, or other thing feels familiar or personally well-known. This is less about friendship and more about a sense of familiarity.
その歌は子供のころから耳に親しい。
That song has been familiar to my ears since childhood.
i-adjective
close as relatives; closely related
Can describe relatives or family connections that are close or closely related; in real use this often overlaps with emotional closeness or a close social tie.
葬儀には親しい親族だけが集まった。
Only close relatives gathered for the funeral.