The 생 in 인생 meaning comes from the Hanja 生 which meaning is tied to life and living. You’ll find 생 in a lot of words; from a social life, birth, and even over to students!
Again, I want to say don’t be scared off by Hanja and think you have to start memorizing Chinese characters along with Korean! I like making these lists so we can gain more insight and intuition in Korean, just knowing that 생 can be tied to life and living can help you guess what new words may mean. Just like in English when you hear “un-something” you know it means the opposite, or “anti-something” you know that it is against or opposing.
Plus I find it fun sometimes to find the original meaning/origin of a word like 외국인 directly meaning “external country person” in the original Hanja. Anyway, let’s get into the Vocab!