intimate (adj.) [...] 1630s, "closely acquainted, very familiar," from Late Latin intimatus, past participle of intimare "make known, announce, impress," from Latin intimus "inmost" (adj.), "close friend" (n.), superlative of in "in" (see in- (2)).
intimare = [...] II. Transf. [...] B. To announce, publish, make known, intimate
What semantic notions underlie "suggest indirectly" to "closely acquainted, very familiar"? Please see the titled question.
The former ("suggest indirectly") obviously connotes indirectness. In contrast, the latter connotes connoted bareness and forthrightness.
The quote below also judges this semantic drift as a reversal in meaning. But I don't understand its last sentence: how might've '“intimate” exerted a moderating influence on the verb over time'?
Interestingly, “intimate” is also a verb, but it followed completely different route into English from that of “intimate” as a noun or adjective. (It’s also usually pronounced differently, with a long “a” in the third syllable.) While “to intimate” today means “to suggest indirectly or imply,” its source was the Latin “intimare,” meaning “to announce,”
and in English “to intimate” originally meant “to make known, notify formally, announce” or even “to declare” in the case of war. That’s quite a reversal for “to intimate.” It’s possible that the cuddly adjective “intimate” exerted a moderating influence on the verb over time, and “to intimate” became less about shouting things in public and more about slyly suggesting them in the privacy of one’s own parlor.