Adam Clarke on 2 Kings 21:6

Made his son pass through the fire - Consecrated him to Moloch.

Observed times - ועונן veonen; he practiced divination by the clouds; by observing their course at particular times, their different kinds, contrary directions, etc., etc.

Used enchantments - ונחש venichesh; he used incantations, spells, and charms.

Dealt with familiar spirits - ועשה אוב veasah ob; he was a necromancer; was a raiser of spirits, whom he endeavored to press into his service; he had a Python.

And wizards - וידענים veyiddeonim; the knowing ones, the white witches, and such like; see on Lev 19:26-31 (note), where most of these terms are particularly explained and illustrated.