It is a phrase that expresses the feeling of having a lasting impression of someone, even if they are no longer present in your life. It can be interpreted as:
* Someone who has had a profound impact on you: This could be a romantic partner, a close friend, or a family member.
* Someone who you deeply admire or respect: This could be a mentor, a teacher, or a role model.
* Someone who has left a lasting memory: This could be someone you met briefly but who made a significant impact on you.
The phrase conveys a sense of longing, nostalgia, and perhaps even a touch of sadness, depending on the context.