무기물이 · 무기물을
inorganic matter, mineral
Example
물과 소금은 대표적인 무기물입니다.
Water and salt are typical inorganic substances.
Word parts
무 without+기 mechanism+물 thing
Literally 'things without a living mechanism'. 무- = 'without': 무료, 무기물.
Good to know
Careful: 무기 alone usually means 'weapon', a completely different word.