Acts 23:12-13
12 And when it was day, certain of the Jews banded together, and bound themselves under a curse, saying that they would neither eat nor drink till they had killed Paul.
13 And they were more than forty which had made this conspiracy.
(KJV)
Ezek 22:23-25
23 And the word of the LORD came unto me, saying,
24 Son of man, say unto her, Thou art the land that is not cleansed, nor rained upon in the day of indignation.
25 There is a conspiracy of her prophets in the midst thereof, like a roaring lion ravening the prey; they have devoured souls; they have taken the treasure and precious things; they have made her many widows in the midst thereof.
(KJV)
Jer 11:9-12
9 And the LORD said unto me, A conspiracy is found among the men of Judah, and among the inhabitants of Jerusalem.
10 They are turned back to the iniquities of their forefathers, which refused to hear My words; and they went after other gods to serve them: the house of Israel and the house of Judah have broken My covenant which I made with their fathers.
11 Therefore thus saith the LORD, Behold, I will bring evil upon them, which they shall not be able to escape; and though they shall cry unto Me, I will not hearken unto them.
12 Then shall the cities of Judah and inhabitants of Jerusalem go, and cry unto the gods unto whom they offer incense: but they shall not save them at all in the time of their trouble.
(KJV)
II Ki 15:30
30 And Hoshea the son of Elah made a conspiracy against Pekah the son of Remaliah, and smote him, and slew him, and reigned in his stead, in the twentieth year of Jotham the son of Uzziah.
(KJV)
2 Sam 15:12-13
12 And Absalom sent for Ahithophel the Gilonite, David's counsellor, from his city, even from Giloh, while he offered sacrifices. And the conspiracy was strong; for the people increased continually with Absalom.
13 And there came a messenger to David, saying, The hearts of the men of Israel are after Absalom.
(KJV)
There's no magic to the word "conspiracy". It simply means a plot or alliance towards acts. Most often when used in God's Word, it involved evil acts.
The grand conspiracy of Satan against Christ today in this world is nothing new.