The word "insurmountable" means something that cannot be overcome or surpassed, especially by someone or something. It is an adjective used to describe a challenge, obstacle, difficulty or problem that seems too difficult or impossible to solve or conquer. The term can also refer to an obstruction or barrier that cannot be crossed or passed through. In essence, "insurmountable" implies an unconquerable and formidable foe, hindrance or challenge that defies resolution or defeat.