Which word describes a roughness or severity in demeanor or tone?

The word that accurately denotes a roughness or severity in demeanor or tone is "asperity." This term originates from the Latin root "asper," which means rough or coarse. It is commonly used to describe a harshness in speech or attitude that can come across as abrasive or severe. For instance, when someone speaks with asperity, their tone likely conveys irritation or sharpness, indicating a lack of the usual gentleness or warmth one might expect in conversation.

In contrast, the other choices do not align with the idea of roughness or severity. "Attenuate" refers to making something weaker or less intense, which does not capture the notion of harshness. "Auspice" pertains to guidance or support, usually in a favorable sense, while "beatify" means to make blessed, often in a spiritual context. Therefore, "asperity" is the most fitting choice, as it directly relates to a severity in demeanor or tone.