English “dead” in Romans 6:9 was translated from Greek adjective 3498 nekros describing a human being who is either spiritually or physically dead.
English “dieth” in Romans 6:9 was translated from Greek verb 599 apothnesko from a compound of Greek preposition 575 apo denoting separation of one thing in deference to another and Greek verb 2348 thnesko subjectively meaning to cause to be either spiritually or physically dead and objectively means to be caused to be either spiritually or physically dead.
English “death” in Romans 6:9 was translated from Greek masculine noun 2288 thanatos being either spiritual or physical death.