I learned a word 필업식 but I'm not sure what is the difference between 필업 and 졸업. So far I have only heard the word 졸업. Is there any difference, even just a subtle nuance, between these two words?
From Naver online dictionary:
필업 (畢業) [명사] 하고 있던 학업이나 사업을 마침. [유의어] 졸업, 종업2
So it seems they are synonyms
If you go to the link above it also shows below the main entry:
필업 [오픈사전] 학업이나 작업을 마친다는 북한말
I don't know how exactly the 오픈사전 feature works, but it seems like viewer contribution and not necessarily from Naver. However, Naver seems to have kept this entry up so perhaps it means they deem this accurate.
I'm Korean and I've never used "필업" in my life for more than 30 years.
I think "졸업" is something that happens in school and "필업" is something that includes happens personally.
"졸업" is a word that follows the existence of students and schools, "필업" isn't.
For example, if my grandfather had a "졸업식", I could expect him to have attended school and had a graduation ceremony at school, but if he had a "필업식", I can't be sure if he did it at school.
I don't know how it is in NK, It only applies to SK.