Sometimes, our use of language, can be used in such a way, to imply or suggest ideas, that upon closer examination are not particularly coherent.
I would like to suggest that "greed" is one such use of language to imply something of an incoherence of an idea.
Because dictionaries often describe the definition or meaning of words as they are most commonly used in the language, they are often not apt not to contain other, more technical definitions, I often suggest that a dictionary is not the best source for linguistic meaning but in this case, I think it will suffice.
greed : a selfish and excessive desire for more of something (as money) than is needed
Examples of GREED: He was a ruthless businessman, motivated by naked ambition and greed.
Human beings act because they have some feeling of uneasiness concerning their current conditions. Human action is decision to act according to a selected strategy that would most likely relieve one's sense or feeling of uneasiness.
For if this were not the case, then why would anyone act at all, if they had no sense of uneasiness/unsatisfactoriness at all?
Therefore, all human-beings act according to their own feelings of uneasiness and act according the strategies they think will most efficiently relieve their felt uneasiness. Said another way, all human-action is necessarily, a conscious choice to act according to the individual's desire to reach a more satisfactory state; which is to say, as long as we assume that human beings make choices at all, they necessarily make choices to satisfy their own preferences/preferred-outcomes.
I see no way to escape these conclusions so long as we assume that people make legitimate choices at all, and barring any form of mind-control or consciousness-sharing (and even these two later conditions may not resolve the conclusion in another way).
If we are then logically bound to the conclusion that all human action is aimed at relieving one's self from felt uneasiness and that therefore people act according to their own ability to choose strategies that would most effectively relieve their felt uneasiness, we must recognize that all human action is necessarily self-interested action.
This being establish, we may see our term "greed" now for the incoherent idea that it is; "greed" becomes an adjective that one necessarily self-interested person uses to describe the actions/motivations of another self-interested person, as a way of saying, "You shouldn't be so self-interested." "Greed" then is the adjective that the self-interested Bob uses to describe the self-interested actions Jill, that Bob does not like. Bob is expressing a preference that Jill would act in some other way, that would benefit Jill less and benefit Bob or some other person(s) more. Bob selects the word "greedy" because he is attempting to use morality to shame Jill; Bob, out of his own self-interest, is saying that Jill should feel shame because Jill's actions are self-interested.
This I suggest, is not a particularly coherent use of language and rather than say, "You are greedy.", we would do better to rephrase that expression to more accurately state our meaning, "I would prefer it, if your actions did not conflict with my own self-interest in such a way."