'Acting' in the Bible

His father had never challenged him at any time during his life by asking him, "Why are you acting like this?" Adonijah was very handsome and had been born after Absalom.

Come now, go to King David and say to him, Did you not, O my lord, take an oath to me, your servant, saying, Truly Solomon your son will be king after me, seated on the seat of my kingdom? why then is Adonijah acting as king?

Give ear in heaven your living-place, acting in mercy; and give to every man whose secret heart is open to you, the reward of all his ways; for you, and you only, have knowledge of the hearts of all the children of men:

Now the king of Israel and Jehoshaphat, the king of Judah, were seated on their seats of authority, dressed in their robes, by the doorway into Samaria; and all the prophets were acting as prophets before them.

Now there was no king in Edom; a deputy (governor) was [serving as] king.