mid-15c., "action of making known," from Old French intimation (14c.), from Late Latin intimationem (nominative intimatio) "an announcement," noun of action from past-participle stem of Latin intimare "make known, announce, impress" (see intimate (adj.)). Meaning "action of expressing by suggestion or hint, indirect imparting of information" is from 1530s.
mid-14c., "intimate, very friendly, on a family footing," from Old French famelier "related; friendly," from Latin familiaris "domestic, private, belonging to a family, of a household;" also "familiar, intimate, friendly," a dissimilation of *familialis, from familia (see family).
From late 14c. as "of or pertaining to one's family." Of things, "known from long association," from late 15c. Meaning "ordinary, usual" is from 1590s.
The noun meaning "demon, evil spirit that answers one's call" is from 1580s (familiar spirit is attested from 1560s); earlier as a noun it meant "a familiar friend" (late 14c.). The Latin plural, used as a noun, meant "the slaves," also "a friend, intimate acquaintance, companion."
"old familiar friend, intimate companion," 1660s, chrony, Cambridge student slang, probably from Greek khronios "long-lasting," from khronos "time" (see chrono-), on the notion of "old friend" or "a contemporary."