Most solved is a term used to describe a problem, puzzle or equation that has been solved by a large number of people. The antonyms for the phrase could be "unsolved," "unresolved," "unsolvable," "mystifying," "baffling," "enigmatic," "perplexing," or "puzzling." These terms describe a question or problem that has not yet been answered, and may require further investigation, research or analysis. In some cases, it may even be impossible to solve or resolve. Therefore, the opposite of most solved is a problem that is yet to be figured or understood, challenging the intellect and persistence of those who seek an answer or solution.