G-forces during gravitational slingshot maneuvers

[Strigon]

I'll just add that an essentially-uniform acceleration field over a given volume isn't necessary "safe" even though everything is accelerating together - your body is meant to function in an environment with an essentially-uniform acceleration field of the strength of 1 standard (Earth) gravity. It will not function nearly as well in an environment with an essentially-uniform acceleration of the strength of, say, 5 standard gravities, and being exposed to such conditions - especially for a prolonged period of time - could do you significant harm; a sufficiently strong gravitational field could potentially kill you outright without any need for tidal forces to rip you apart.

If you're talking about in orbit - as in, not on the ground, so not being pushed into anything - you're completely wrong about that.
One could experience literally any gravitational force and survive, as long as it was evenly distributed and not pushing you into the ground. A gravitational field wouldn't do any harm to you on its own.

In fact - and I could be talking complete rubbish here, or at least an extremely simplified version of the truth - but I seem to recall that, in truth, you wouldn't even be accelerating at all. I mean, you are, in that your velocity is changing relative to everything around you, but my understanding is that gravity bends spacetime, so that what the universe considers to be a straight and level path actually involves curving and accelerating from an outside perspective. For all intents and purposes, though, until you hit something else, you're just sitting there.


On this topic, though, can someone please explain why the term "microgravity" is considered more technically correct than "zero-G"? I mean, I've heard the explanations, and I'm entirely unconvinced. After all, "G" forces are used to measure acceleration that's felt, generally; we say a person standing on the surface of the earth is under 1 G, even though they aren't actually accelerating. By that logic, anyone in orbit should be experiencing 0 G.
But microgravity makes absolutely no sense, because it implies that the gravitational force has just been greatly diminished, and that's why things behave as though they're weightless. However, that's demonstrably less true than the whole argument about G-forces, because the gravitational force only decreases a tiny amount in our typical orbits, and in some cases is actually higher.
Is there a compelling reason that I'm missing why zero-G is considered a misnomer, and microgravity is considered correct?
Is that even the correct terminology, or was I taught incorrectly?

Edit:

You got most of the physics correct except for one problem. A slingshot around a star will not increase your speed. Slingshots only change your speed if there are two other bodies, say the Earth and the Moon. By slingshotting around the Moon, you are very slightly decreasing the Moon's orbit speed to increase your own. Without a third body to have an orbit, you cannot change your speed.

This is true, but if an object is slingshoting around a star, it seems likely that it's an interstellar traveler. One could easily imagine an object leaving one star system, orbiting around the galactic center, and getting a gravity assist from another star system. It would take a long, long, long time, especially since 0.25c was only achieved after the slingshot, but there's no reason it couldn't be done.