I'm watching a drama and heard somebody say '같잖아서 원' as they were getting angry - '같잖아서 원... 영재 하는 대로 따라하면 무조건 붙는대?' (yes - it's from Sky Castle). I know that 같잖다 means foolish but could anybody clear up whether '같잖아서 원' is a fixed phrase and whether it's actually used much in real life? Thanks in advance.
"~서 원" is the form commonly used in colloquial Korean. You can use it to emphasize a situation or things that are usually bad for you. (sometimes good things with irony.) Some examples are "추워서 원.", "웃겨서 원.", "귀찮아서 원.". '원' can be substituted by some other interjections, like "웃겨서 참 내.", "추워서 진짜.". ('진짜' is more used by younger people, compared to '원'.)
"추워. (It's cold.)" is a normal sentence and "추워서 원." is an emphasized sentence. (So it can be translated as "It's freezing cold.")
To tell this more, "~서 원" is actually the cut-off form of "~서 (원,) (another sentence)". Maybe you know '~서' is 'so'. So you can say "추워서 (원,) 나갈 수가 없다." ("It's cold so I can't go outside." (as word-to-word translation) = "It's freaking cold. I don't feel like going outside.")
But Koreans don't feel "~서, 원" as the unfinished sentence. As above said, Koreans feel and use this as a emphasized sentence in a colloquial situation. So it's the linguistic characteristic of Korean language to use an unfinished sentence as a finished sentence, which is also common in Japanese.
In addition, '같잖다' has some despising, insulting nuance.
This link shows a more accurate sense of the word. https://krdict.korean.go.kr/eng/dicSearch/search?nation=eng&nationCode=6&mainSearchWord=%EA%B0%99%EC%9E%96%EB%8B%A4
같잖다 1. unseemly; absurd Someone's behavior or attitude being detestable and unlikable. 2. trivial; insignificant Too trivial to be worthy of being talked or thought about. Someone's behavior or attitude being detestable and unlikable.
The first sense is derived from the second one.
It is not a fixed phrase. 같잖다 is commonly used in real life. For example,
A: 야, 한 판 할까? (Hey, wanna play a game?)
B: 귀찮다. (I don't feel like it.)
A: 왜? 쫄았냐? (Why? Are you intimidated?)
B: ㅋㅋ 같잖다.
One says someone is 같잖다 if one think that they are behaving like they are better than they actually are, or when their behavior is a nonsense which is not even fun.