expression, noun
precious life
A somewhat formal or literary expression emphasizing the value and irreplaceability of life. Often used in contexts of protecting life or reflecting on its worth.
貴い命を守るために、全力を尽くします。
I will do everything in my power to protect this precious life.
戦争で多くの貴い命が失われた。
Many precious lives were lost in the war.
尊い is a more common adjective for 'precious' or 'sacred', while 貴い is a variant often used in fixed expressions like 貴い命.
命 alone means 'life'; 貴い命 adds the nuance of preciousness and is more emphatic.
Combination of 貴い (たっとい, 'precious, noble') and 命 (いのち, 'life'). 貴い is a less common variant of 尊い (とうとい).