This is always a good discussion: How should you get a trail name, and what is acceptable?
My feeling on "acceptable" is that some commonsense and at least a little good taste are essential. I was, frankly, a little put off (well, more than that) when I came across a young (17-18) girl who had adopted the name, "Trail Bait". That's a risky thing for a girl (any age) to do on the AT. A few others like "B--- Sh---er" and the like are also part of the reason why thruhikers aren't as welcome in some towns, where people have both tolerance but a fair amount of respect for decency.
As to getting one, I'm on the side of what I call "Zen" trail names...the ones that find you, and not the other way around. I got mine from another thruhiker who told his family about the lawyer he was going to hike with was "the weasel I know". It stuck, and it has a certain perverse humor to it. "Hack Saw" was noted for his snoring, and "Yogi" because of a knack for mooching food from picnickers. I think that such a name is a form of honor bestowed by others on the trail. If you "pick your own" sort of like a trucker with a CB "handle", you lose some of the delight - a form of "trail magic" - that hits you BIG TIME when you drag into a shelter, tired, stinking and hungry on a crappy day, and you see one of your friends as he tells someone, "Yeah, that's The Weasel I was telling you about." And you realize that, "Wow!" It happened.
Might not happen fast...might not happen for a long time...might not even happen at all. But it's total cool when it does.
That's why I encourage people to hold off from a "real" trail name until they get close to or on the Trail.
The Weasel
"Well a promise made, is a debt unpaid, and the Trail has its own stern code." -- Robert Service