lookism
외모지상주의
Have you met my new manager? He is a mess! Doesn’t he ever shave?
내 새로운 매니저 만나봤어? 그 사람 정말 지저분해! 그 사람은 면도도 안 하나?
Don’t judge a book by its cover.
겉만 보고 판단하지 마.
The English idiom "don't judge a book by its cover" is a metaphorical phrase that means one should not judge the worth or value of something by its outward appearance alone.
For example, "That man may look very small and insignificant, but don't judge a book by its cover – he's a very powerful man in his circle"
Don't judge someone based on what you hear - but rather what you know.
Roughly translated 외모지상주의 is superficialism. But, superficialism and lookism has slightly different meaning. So, it depends.
But yeah, as how 외모지상주의 is, this words aren't generally used in daily conversation.