This is the 3397th most frequent Japanese word.
死に
"死に" translates to "death" or "dying" in English, often used as a stem or descriptive form in phrases.
死に here is the verb stem of 死ぬ (to die), combined with ます (a polite ending). It signifies someone's passing in a polite context.
彼は若くして死にました。
He passed away at a young age.
死に is used here in conjunction with そう (seeming) to express an exaggerated feeling of extremity, typical in casual expressions.
こんなに寒いと死にそうです。
With this cold, I feel like I might die.
死に物狂い combines 死に with 狂い (madness) and is used metaphorically as a set phrase to indicate extreme effort or desperation.