Which verb refers to officially declaring something?

The verb that best refers to officially declaring something is "proclaim." This term is used in contexts where an announcement is made publicly or formally. It carries connotations of authority and certainty, often associated with declarations of significance, such as proclaiming a holiday, announcing a law, or stating a fact.

The other choices do not relate to the act of declaring officially. "Compunction" refers to a feeling of guilt or moral scruple that prevents or follows the doing of something bad, while "inexorable" describes something that is relentless or unyielding, often used in contexts that depict an unstoppable force. "Poignant" is an adjective that evokes a strong emotional response, usually sadness or regret, rather than implying any form of declaration. Thus, "proclaim" stands out as the only term that matches the requirement of an official declaration.