1. What does it mean?
호불호 refers to positive and negative preferences. 호불호가 갈리다 means people are divided about something, while 호불호가 뚜렷하다 describes someone with clear likes and dislikes.
Also written or said as hobulho
2. The nuance
A divisive dish or movie is not necessarily low quality. The expression is not inherently slang, but appears frequently in informal reviews because it separates taste from a universal verdict.
3. Examples
“이 향수는 향이 강해서 호불호가 갈리겠다.”
This perfume has a strong scent, so people will probably be divided on it.
“나는 디저트는 좋아하지만 식감에는 호불호가 뚜렷해.”
I like desserts, but I have definite preferences about texture.
Sources
National Institute of Korean Language
References support the meaning and usage. Example sentences are written for NoCapWiki.