What’s the meaning of 구 in the word 구남친?

Question

I can’t find where the syllabus 구 comes from. What does 구 mean?

Answer 1

As @user2326230 said, '구' in the '구남친' means old or ex-.

This 구 is written as 舊 in Chinese. https://hanja.dict.naver.com/#/entry/ccko/cf039f0ab84541778e6a31794fb76889

新 has the opposite meaning 'new'. Thus 구 and 신 are often used together as a single word '신구(新舊)' meaning old and new as in a phrase 新舊交代 (Exchange between the old and the new).

Answer 2

As user13229973 mentioned, '구' means 'old' or 'past'. '구' or '전' 남친 can be translated to 'ex-boyfriend'. But, I'm not sure if this is what the originator wants. There would be more accurate answer if a sample sentence be provided.