필수(pil-su, pilsu)
Something mandatory or absolutely necessary
When to use
legal requirement, mandatory education, health care
The nuance
Use 필수 when something is required by rules, laws, or circumstances without personal choice.
필수 vs 선택: Must-have vs Optional Choices
필수 (pil-su, pilsu) · 선택 (seon-taek, seontaek)
필수 (pil-su) means something mandatory, while 선택 (seon-taek) means something optional or chosen.
Word-by-word breakdown
One lane per word — no nested boxes, just the gist.
선택(seon-taek, seontaek)
Something that can be freely chosen among options
When to use
hobby activities, choosing menu, deciding outfit
The nuance
Use 선택 when the decision depends on personal will and is not mandatory.
Real-world examples
이 과목은 필수입니다.
i gwa-mok-eun pil-su-ip-ni-da., i gwa mok eun pil su ip ni da.
Use 필수 for subjects that must be taken.
이 과목은 선택입니다.
i gwa-mok-eun seon-taek-ip-ni-da., i gwa mok eun seon taek ip ni da.
Use 선택 for subjects that are optional.
건강 검진은 선택입니다.
geon-gang geom-jin-eun seon-taek-ip-ni-da., geon gang geom jin eun seon taek ip ni da.
Health checkups can be mandatory by law, so 선택 is incorrect here.
운동은 필수입니다.
un-dong-eun pil-su-ip-ni-da., un dong eun pil su ip ni da.
Exercise is recommended, not mandatory, so 필수 is incorrect.
메뉴 선택은 선택입니다.
me-nyu seon-taek-eun seon-taek-ip-ni-da., me nyu seon taek eun seon taek ip ni da.
Choosing a menu is a personal choice, so 선택 is correct.
메뉴 선택은 필수입니다.
me-nyu seon-taek-eun pil-su-ip-ni-da., me nyu seon taek eun pil su ip ni da.
Choosing a menu is not mandatory, so 필수 is incorrect.
출석은 필수입니다.
chul-seok-eun pil-su-ip-ni-da., chul seok eun pil su ip ni da.
Use 필수 when attendance is required.
출석은 선택입니다.
chul-seok-eun seon-taek-ip-ni-da., chul seok eun seon taek ip ni da.
If attendance is required, 선택 is incorrect.
Quick quiz
Which subject must be taken at school?
학교에서 꼭 들어야 하는 과목은?(hak-gyo-e-seokkokdeul-eo-yaha-neungwa-mok-eun?, hakgyoeseokkokdeuleoyahaneungwamokeun?)What can be freely chosen by an individual?
개인이 자유롭게 고를 수 있는 것은?(gae-in-ija-yu-rop-gego-reulsuiss-neungeos-eun?, gaeinijayuropgegoreulsuissneungeoseun?)What is mandated by law?
법으로 정해져 반드시 해야 하는 것은?(beop-eu-rojeong-hae-jyeoban-deu-sihae-yaha-neungeos-eun?, beopeurojeonghaejyeobandeusihaeyahaneungeoseun?)What category do hobby activities fall into?
취미 활동은 어떤 경우에 해당하는가?(chwi-mihwal-dong-euneo-tteongyeong-u-ehae-dang-ha-neun-ga?, chwimihwaldongeuneotteongyeonguehaedanghaneunga?)
More comparisons to explore
- 선택하다 vs 고르다: Nuance Differences in Making Choices
- 능동 vs 수동 vs 피동: Differences in Expressing Subject and Action
- 밥 vs 면: Choosing the Right Korean Food Word
- 경험 (Gyeongheom) vs 완료 (Wanryo): Difference Between Experience and Completion
- 더 vs 덜: Comparison and Differences
- 복습하다 vs 공부하다: When to Use Each?
- Guk vs Jjigae: Differences in Korean Soups and Stews
- Mastering the Differences: 속어 vs 비속어 vs 은어