Which term means to approve in a formal or authoritative way?

The term that means to approve in a formal or authoritative way is "sanction." In legal or official contexts, to sanction something often implies giving it formal approval or authorization. For instance, a governing body may sanction a new law, which means they officially endorse or accept it as valid and enforceable.

In contrast, the other options have different meanings. "Sovereign" refers to a supreme ruler or authority and does not inherently imply approval. "Severance" typically relates to the termination of a relationship or connection, often used in legal or employment contexts, while "satiate" means to satisfy fully, particularly in reference to appetite or desire, and does not convey the idea of formal approval. Thus, "sanction" is the appropriate term that captures the essence of formally approving something.