Officially designated rest days, such as public holidays or weekends
When to use
Public holidays, Weekends, Statutory days off
The nuance
Use 휴일 for days officially designated as days off by companies or government, indicating non-working days.
휴일 (hyu-il, hyuil) · 근무일 (geun-mu-il, geunmuil)
휴일 (hyuil) means official rest days, while 근무일 (geunmu-il) refers to actual workdays.

One lane per word — no nested boxes, just the gist.
Officially designated rest days, such as public holidays or weekends
When to use
Public holidays, Weekends, Statutory days off
The nuance
Use 휴일 for days officially designated as days off by companies or government, indicating non-working days.
Days when one actually works, days when you go to work
When to use
Weekday workdays, Scheduled working days, All working days excluding holidays
The nuance
근무일 refers to days when employees go to work and perform duties, i.e., non-holidays.
이번 주 토요일은 휴일이에요.
i-beon ju to-yo-il-eun hyu-il-i-e-yo., i beon ju to yo il eun hyu il i e yo.
Saturday is officially a rest day, so 휴일 is correct.
이번 주 토요일은 근무일이에요.
i-beon ju to-yo-il-eun geun-mu-il-i-e-yo., i beon ju to yo il eun geun mu il i e yo.
Saturday is generally a holiday, so 근무일 is incorrect here.
평일은 모두 근무일입니다.
pyeong-il-eun mo-du geun-mu-il-ip-ni-da., pyeong il eun mo du geun mu il ip ni da.
Weekdays are usually working days, so 근무일 is correct.
평일은 모두 휴일입니다.
pyeong-il-eun mo-du hyu-il-ip-ni-da., pyeong il eun mo du hyu il ip ni da.
Weekdays are generally workdays, so 휴일 is incorrect here.
국경일은 공식 휴일입니다.
guk-gyeong-il-eun gong-sik hyu-il-ip-ni-da., guk gyeong il eun gong sik hyu il ip ni da.
National holidays are legally designated rest days, so 휴일 is correct.
국경일은 근무일입니다.
guk-gyeong-il-eun geun-mu-il-ip-ni-da., guk gyeong il eun geun mu il ip ni da.
National holidays are rest days, so 근무일 is incorrect.
오늘은 근무일이라 출근해야 해요.
o-neul-eun geun-mu-il-i-ra chul-geun-hae-ya hae-yo., o neul eun geun mu il i ra chul geun hae ya hae yo.
If today is a working day, 근무일 is appropriate.
오늘은 휴일이라 출근해야 해요.
o-neul-eun hyu-il-i-ra chul-geun-hae-ya hae-yo., o neul eun hyu il i ra chul geun hae ya hae yo.
On a 휴일, you don't go to work, so the sentence contradicts itself.
Which day is NOT a 휴일?
Which sentence correctly uses 근무일?
Which is true about 휴일?