I find etymology endlessly fascinating and there is, for sure, a temptation. Knowing where words come from can lead you to want to think of the original or root meaning as the “real” one even if, long since, that meaning has been emptied and replaced. Case in point: hotel, hostel, and hospital all derive from the Latin word hospes meaning guest or host. Oh, host too derives from it. That’s an interesting fact, reasonable, and illuminating, but that doesn’t erase the bright lines of difference between those different places in the English-speaking world.
Sometimes the cultural oblivion of roots leads to some funnier results. Here in English, “alone” is a truncated form of “all one,” meaning “one in total” or something to that effect—you know, by yourself, alone. Similarly, the word “lonely” is (1) further shortened by the dropping of the initial a, but also (2) lengthened with the suffix “-ly” meaning “-like”: “alone-like.” Paradoxically, this sounds like it means “merely like being alone but not actually alone,” which I suppose it can in the context of an individual in a crowd, but it also frequently describes people who are in fact physically alone—I guess the idea being that the quality that is so distinct to being alone that in a different context would make it qualify as “alone-like” is so pronounced that it’s intense, rather than merely similar.
So that’s where “alone” and “lonely” come from. The funny thing, of course, is that both of those words now have the specific meanings they have. This means that they can be further intensified by contrast with each other or by the addition of the word “all.” You can describe someone as “all alone” or “alone, but not lonely” with a straight face.
This isn’t unique to English. In Greek, the words for “every” and “word” were combined into a compound word that means “frankness” or “plainness” or “free approach”—when you’re speaking in direct language, or completely transparently with someone you can be yourself around. In turn, it also had the option of meaning “confidence” or “boldness” in general.
So in Mark 8 (ESV) we see the “plain” meaning (word in bold):
And he began to teach them that the Son of Man must suffer many things and be rejected by the elders and the chief priests and the scribes and be killed, and after three days rise again. And he said this plainly.
Ephesians 6 sees two uses of the word back to back, referring to confident speech:
To that end, keep alert with all perseverance, making supplication for all the saints, and also for me, that words may be given to me in opening my mouth boldly to proclaim the mystery of the gospel, for which I am an ambassador in chains, that I may declare it boldly, as I ought to speak.
In Philippians 1, though, Paul uses the word more generically to just mean boldness, disconnected from any particular speech:
Yes, and I will rejoice, for I know that through your prayers and the help of the Spirit of Jesus Christ this will turn out for my deliverance, as it is my eager expectation and hope that I will not be at all ashamed, but that with full courage now as always Christ will be honored in my body, whether by life or by death.
The funny thing about the Philippians usage, though, is that Paul modifies the word with the adjective here translated “full” but typically rendered as “every” or “all”: ἐν πάσῃ παρρησίᾳ. That is, in fact, the word initially coopted to form the compound word meaning “plain speech” or “boldness” in the first place; the language is analogous to the English “all alone.”
I think that’s an interesting thing to pick up on; also, it’s not a bad use of language. It’s meaningful—a hospital is not a hotel—even if our inner pedant might see red at first blush.