Which term applies to behaviors that society feels very strongly about, often resulting in serious consequences if violated?

The correct term to describe behaviors that society feels very strongly about, often resulting in serious consequences if violated, is mores. Mores are the accepted traditional customs and rules that are considered essential to the social fabric and moral order of a society. These behaviors and practices are not just socially expected; they hold significant moral weight. When individuals violate mores, it can lead to strong reactions from the community, including legal repercussions and social ostracism.

In contrast, while taboos also represent behaviors that are highly discouraged, they tend to refer to more severe prohibitions and often involve deep cultural sensitivities. Customs refer to established and accepted practices that might not carry the same moral implications, and social norms encompass a broader range of behaviors that society generally expects, but without the same weight of moral obligation as mores. Thus, the strongest alignment with serious societal consequences comes from mores.