Amy does not like how her mother-in-law treats her, and has had enough of it. This year, she refuses to go to her in-laws' for the family holiday dinner, and insists that the kids stay home with her as well. Amy is exhibiting

belligerence.

Explanation:

In psychology, the term "belligerent" is described as an individual, country, or group, etc that behaves in a hostile or aggressive manner, for example, a person who is being involved in "combat".

In other words, a belligerent person is one who always wants to engage oneself in a war-like situation or ready to fight or argues with another person.

Belligerence is the process that involves a belligerent person.

In the question above, Amy is exhibiting belligerence.