The prefix "arch-" can indicate authority, excellence, or extremity. Synonyms for "arch-" include chief, principal, leading, paramount, superior, top, best, first-rate, exceptional, extraordinary, and surpassing. When used to indicate extremity, "arch-" may also be replaced with over, hyper, super, or ultra. For example, the phrase "arch-nemesis" could be changed to "principal adversary" or "leading enemy." "Archaic" could be replaced with "old-fashioned" or "outdated," while "archbishop" could be substituted with "chief bishop" or "primary clergyman." Knowing alternative ways to express the idea behind "arch-" can expand your vocabulary and give your writing a more varied and sophisticated tone.