The word "avarice," meaning excessive greed,...
appears twice. The first time it appears is in the paragraph with "greedy."
For again Scrooge saw himself. He was older now; a man in the prime of life. His face had not the harsh and rigid lines of later years; but it had begun to wear the signs of care and avarice. There was an eager, greedy, restless motion in the eye, which showed the passion that had taken root, and where the shadow of the growing tree would fall. (Stave 2)
The second time "avarice" appears is when Scrooge questions the meaning of his life as he stands at the foot of a man's deathbed, possibly his own.
He thought, if this man could be raised up now, what would be his foremost thoughts? Avarice, hard-dealing, griping cares? (Stave 4)
Dickens's first description of Scrooge in A Christmas Carol reads:
Oh! but he was a tight-fisted hand at the grindstone, Scrooge! a squeezing, wrenching, grasping, scraping, clutching, covetous old sinner! (Stave 1)
Similar to "greedy," "covetous" means craving wealth or possessions. Scrooge doesn't necessarily covet anything he hasn't earned for himself—he feels he has worked hard for many years for the money he's accumulated, and he simply intends to keep as much of it as possible. Dickens, however, points out the selfish and uncharitable nature of this attitude.
Though the word doesn't appear in the text of the novella, Scrooge can be described as a miser—someone who is stingy and ungenerous with his wealth. He might have been more explicitly greedy or even avaricious at some earlier time in his life, but at the time of his visit from the three spirits, he's more miserly than greedy. Scrooge could also be considered frugal, which under ordinary circumstances might be considered a positive trait. The problem is that Scrooge's frugality is unnecessary and has negative consequences for his employees, as well as for himself.
Scrooge's miserly behavior arises from his abject fear of poverty, which is what motivated Scrooge's greed earlier in his life.
“This is the even-handed dealing of the world!” he said. “There is nothing on which it is so hard as poverty; and there is nothing it professes to condemn with such severity as the pursuit of wealth!” (Stave 2)
One of the messages of A Christmas Carol that Dickens hopes to impart to its readers is that the accumulation of wealth, whether through greed, avarice, or simple miserliness, at the expense of one's own humanity or the humanity of those around him, leads to an empty, lonely, loveless, and ultimately meaningless existence. Family, friends, generosity, compassion, and forgiveness, not wealth, are the foundation of a happy, fulfilling life.