"Mysterial" is a unique word that means "related to mysteries or secrets." There are several synonyms that can be used to convey a similar meaning to "mysterial." One synonym is "enigmatic," which refers to something that is mysterious and difficult to understand. "Cryptic" is another synonym that can be used to describe something that is mysterious and hidden. Additionally, "esoteric" can be used to refer to knowledge that is only known by a select group or those with specialized training. Other synonyms for "mysterial" include "occult," "arcane," and "mysterious." All of these synonyms can be used to describe something that is shrouded in mystery or secrecy, adding intrigue and fascination to whatever is being discussed.