This is the 3097th most frequent Korean word.
ㄱ씨
"ㄱ씨" is not a standard Korean word. It may be a typo or abbreviation, but in isolation, it has no established meaning.
The word "씨" is used here as an honorific title attached to a person's name to address them respectfully.
김지수 씨, 안녕하세요.
Hello, Mr./Ms. Kim Ji-su.
In this context, "씨" denotes polite address when mentioning a person's name in a formal setting.
박민호 씨와 협력하여 프로젝트를 진행했습니다.
I collaborated with Mr./Ms. Park Min-ho to work on the project.
Here, "씨" is incorporated to address Ms. Joo-yeon respectfully when discussing her actions or attributes.