Pleonexia, sometimes called pleonexy, originating from the Greek πλεονεξία, is a philosophical concept which roughly corresponds to greed, covetousness, or avarice, and is strictly defined as "the insatiable desire to have what rightfully belongs to others."
Thrasymachus, in Book I of The Republic, presents pleonexia as a natural state, upon which justice is an unnatural restraint.
The Greeks call the violation of this law πλεονεξία; that is, a desire of more than their share.
William Barclay[5] describes pleonexia as an "accursed love of having", which "will pursue its own interests with complete disregard for the rights of others, and even for the considerations of common humanity".
In the material sphere, it involves "grasping at money and goods, regardless of honour and honesty".