Which word indicates doubt regarding the truth of something?

The word that indicates doubt regarding the truth of something is "skeptical." When someone is skeptical, they tend to question the validity or truthfulness of a concept, claim, or idea rather than simply accepting it at face value. This term encapsulates a mindset of inquiry and doubt, suggesting that the individual is not easily convinced without further evidence or reasoning.

In the context of the other choices, "sanctimonious" refers to a display of excessive righteousness or moral superiority, "schism" describes a split or division, often within a group or organization, and "severance" relates to the act of cutting off or breaking a connection. None of these convey the idea of doubt or questioning truth, making "skeptical" the most fitting choice for this particular query.