This is the 4996th most frequent Korean word.
기간인
The term "기간인" does not appear to be a standard word in Korean. If you meant "기간" (duration/period) or another word, please clarify for further assistance.
기간인 is used as a compound noun representing a set duration in this sentence.
이번 프로젝트의 시험 기간인은 2주간입니다.
The test duration for this project is two weeks.
기간인 is used to describe a duration that is suitable in this context.
여름은 야외 활동이 적당한 기간인 경우가 많습니다.
Summer is often a suitable duration for outdoor activities.
기간인 is used here to signify the time frame discussed.