Tom Walker's wife is a miserly woman who keeps "secret hoards" from her husband, which serves as a source of frequent argument between the two. She is described as a "tall termagant, fierce of temper, loud of tongue, and strong of arm." She doesn't hesitate to fight with her husband and is even prone to hitting the man. This unusually aggressive, violent behavior leads Tom to behave distrustfully around her, and he tries not to reveal any of his private matters to her. Even outsiders are unwilling to come between them to stop their fighting.
Perhaps the greatest argument that the woman belongs to the devil without having to bargain is that Tom himself does not even fear the devil because he is already so closely accustomed with the force of evil that is his wife!
Oh, almost all of them. She embodies many sins (as does Tom in relation to her). As Irving tells us:
"He had a wife as miserly as himself; they were so miserly that they even conspired to cheat each other. Whatever the woman could lay hands on she hid away: a hen could not cackle but she was on the alert to secure the new-laid egg."
So, she's miserly, she's mean, she nags, she conspires, she's loud, she's got a nasty temper, and she's "strong of arm," which I assume means she hits him sometimes.
She's specifically labeled as a "termagant," which means nagging woman, but also a false deity. Taken together, she's pretty much on the dark side.