The tenth commandment forbids greed and the desire to amass earthly goods without limit. It forbids avarice arising from a passion for riches and their attendant power. It also forbids the desire to commit injustice by harming our neighbor in his temporal goods:
When the Law says, "You shall not covet," these words mean that we should banish our desires for whatever does not belong to us. Our thirst for another's goods is immense, infinite, never quenched. Thus it is written: "He who loves money never has money enough."
Source: Catechism of the Catholic Church (Vatican.va)