wholly given to idolatry

Concise Bible Dictionary:

The worship of idols—a sin which is mentioned as committed after the flood. There seems to have been a universal giving up of the knowledge of the true God. Paul, speaking of men, says that when they knew God, they glorified Him not as God, they did not like to retain God in their knowledge, notwithstanding that what may be known of God in nature, His eternal power and Godhead, was manifested to them. They degraded the worship of the true God everywhere, and idolatry became universal. In this, man had no excuse. Images were made like corruptible man, and birds, and four-footed beasts, and creeping things (Rom. 1:20-2320For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: 21Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. 22Professing themselves to be wise, they became fools, 23And changed the glory of the uncorruptible God into an image made like to corruptible man, and to birds, and fourfooted beasts, and creeping things. (Romans 1:20‑23)). From this state Abram was rescued by the God of glory appearing to him. Scripture shows the folly of a man cutting down a tree, and burning part of it to cook his food and to warm himself, and yet making a god of the rest, and worshipping it (Isa. 44:14-1714He heweth him down cedars, and taketh the cypress and the oak, which he strengtheneth for himself among the trees of the forest: he planteth an ash, and the rain doth nourish it. 15Then shall it be for a man to burn: for he will take thereof, and warm himself; yea, he kindleth it, and baketh bread; yea, he maketh a god, and worshippeth it; he maketh it a graven image, and falleth down thereto. 16He burneth part thereof in the fire; with part thereof he eateth flesh; he roasteth roast, and is satisfied: yea, he warmeth himself, and saith, Aha, I am warm, I have seen the fire: 17And the residue thereof he maketh a god, even his graven image: he falleth down unto it, and worshippeth it, and prayeth unto it, and saith, Deliver me; for thou art my god. (Isaiah 44:14‑17)); and yet Israel, to whom God had revealed Himself, not only as Creator but in redemption, adopted these wicked follies. There were also molten images and images of stone.
Imaginary creatures were regarded as gods, and these were feared and propitiated. Some believed in a fetish of good and a fetish of evil. Others had an elaborate system of mythology, as the Greeks, with husbands and wives and sons and daughters of the gods and goddesses. Man himself was exalted by some into a god, as with the Greeks and the Romans.
In Israel at first there might have been the thought that the idol was only a representative of God, just as the Egyptians professed to have representations of their unseen gods. When the golden calf was made Aaron built an altar before it, and said, “Tomorrow is a feast to Jehovah”; but the people said, “These be thy gods, O Israel, which brought thee up out of the land of Egypt” (Ex. 32:4-54And he received them at their hand, and fashioned it with a graving tool, after he had made it a molten calf: and they said, These be thy gods, O Israel, which brought thee up out of the land of Egypt. 5And when Aaron saw it, he built an altar before it; and Aaron made proclamation, and said, To morrow is a feast to the Lord. (Exodus 32:4‑5)). Yet they had been commanded to make no graven image, because they saw no similitude when God spake to them at Horeb. This species of idolatry is seen further developed in the case of Micah, who had a house of gods. See MICAH.
As to the sacrificing being to demons, the same thing is said of the idolatry at Corinth, with its Grecian mythology (1 Cor. 10:2020But I say, that the things which the Gentiles sacrifice, they sacrifice to devils, and not to God: and I would not that ye should have fellowship with devils. (1 Corinthians 10:20)). Satan being the real promoter of it all, he knows how to lead a poor unintelligent heathen to be satisfied with an imaginary fetish; the Greeks and Romans to be pleased with their stately statues; and the Brahmins and Hindus to pride themselves in their superior and refined mysticism. Satan has also succeeded in introducing into the professing church the worship of the Virgin Mary and of the saints. To this must be added another species of idolatry to which Christians are sometimes enticed, namely, that of letting anything but Christ have the first place in the heart; for in Him God is revealed, He “is the image of the invisible God”—“He is the true God.” “Little children, keep yourselves from idols” (1 John 5:2121Little children, keep yourselves from idols. Amen. (1 John 5:21)). The word εἴδωλον is from εῖδος, “that which is seen,” and covetousness is specially characterized as idolatry (Col. 3:55Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry: (Colossians 3:5)).

Strong’s Dictionary of Greek Words:

Number:
2712 (find all occurrences in KJV Bible)
Greek:
κατείδωλος
Transliteration:
kateidolos
Phonic:
kat-i’-do-los
Meaning:
from 2596 (intensively) and 1497; utterly idolatrous
KJV Usage:
wholly given to idolatry