familiar

1. (witchcraft) An attendant spirit, often in animal or demon form.Examples: "The witch’s familiar was a black cat."; "The familiars of the magicians, on the other hand, were not in all cases evil, and often may have approximated the "guides" with whom present-day spiritualists are well acquainted."; ""What power hath gold?" Catweazle wondered as he picked up his familiar and put him in his special pocket."

2. (obsolete) A member of one's family or household.obsolete

3. (obsolete) A close friend.Examples: "[A] friend of mine, that finding a Receipt in Braſsivola, would needs take Hellebor in ſubſtance, & try it on his own perſon; but had not ſome of his familiars come to viſite him by chance, he had by his indiſcretion hazarded himſelfe; many ſuch I have obſerued."obsolete

4. (historical) The officer of the Inquisition who arrested suspected people.historical