noun, noun which may take the genitive case particle 'no'
money-grubber; money-mad person; money monger
A derogatory term for someone obsessed with money, often implying greed and a loss of moral perspective. Used as a noun or with の to modify another noun.
彼は金の亡者で、友達さえ裏切った。
He is a money-grubber who even betrayed his friends.
金の亡者にならないように気をつけたい。
I want to be careful not to become a money-mad person.
拝金主義者 is a more abstract term for a worshipper of money or a materialist, whereas 金の亡者 focuses on the person's greedy, obsessive behavior.
Compound of 金 (かね, 'money') + の (possessive particle) + 亡者 (もうじゃ, 'the dead' or 'departed spirit'). The term 亡者 originally refers to a deceased person, but in this idiom it figuratively means someone who is spiritually dead due to their obsession with money.