Which word refers to something that is unconquerable and refusing to yield?

The term that signifies something that is unconquerable and unwavering in its stance is "indomitable." This word is derived from Latin roots meaning "untamable" or "unbeatable," aptly describing a spirit or will that remains steadfast despite challenges or adversities.

In various contexts, such as literature, history, or personal character, "indomitable" conveys a sense of resilience and strength, reflecting an individual or entity that cannot be defeated or subdued.

Considering the other options, "inert" refers to a state of inactivity or lack of energy, while "insoluble" pertains to something that cannot be dissolved or solved. "Insatiable" describes an unquenchable desire or appetite. None of these terms capture the essence of being unconquerable or resistant to yielding as effectively as "indomitable."