In the passage avarice is used to describe Tom Walker's wife. The contextual clues that help one determine it's meaning is "hidden gold" and "wealthy for life". Since these are the two things that seem to matter to the woman, it can be deduced that avarice means greediness. While she did urge her husband to comply, she is not commanding him - this would suggest bossiness. Also, in this specific part we don't see any evidence that would suggest she is mean or selfish.
