Hypaspist translitterates the Greek term meaning shield-bearer, or armour-bearer (ὁ ὑπασπιστής). This noun is formed from the verb ὑπασπίζειν - to carry the shield for another; serve as a shieldbearer. The Shieldbearers of the Argead kings Philip II and Alexander III were the élite Macedonian infantry corps with important roles in the army and at the royal court, where they seem to have constituted the court guard (as distinct from the somatophylakia, the corps of aristocratic youths who were the bodyguard of the king himself).
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/160/the-hypaspists-in-ancient-sources/.