Einlanzer0
Adventurer
Oh, I was just thinking about this the other day. I think an arcane half-caster would be a great addition to the game, and it seems like a popular archetype in fantasy fiction. Unfortunately, it's hard for me to come up with a good name for this archetype because it covers such a lot of ground. Here are some of the least-bad ideas I've come up with:
Witch Hunter -- a warrior who learns arcane magic in order to fight fire with fire (in some cases, literally). However, the Blood Hunter class seems to have that concept locked down; it's more warlocky than wizardy, but the flavor is definitely there.
Arcane Guardian -- a warrior who protects spellcasters, and in return for their services, learns a little bit of arcane magic. Lots of overlap with 4E swordmage, which was an arcane defender. But, the name "Arcane Guardian" is super weak. (So is "Swordmage.") The best thing I can think of is "Sentinel" but that's a feat already. "Keeper" is not bad.
Warden -- combining the above two concepts, this is a warrior who is part of an order that defends the world against arcane threats. Unfortunately this name is already taken by a somewhat-popular 4E class that is much more druidic in nature than arcane. The flavor matches well, though. "Keeper" or "Overseer" might be good substitutes; "Magekeeper?" (Sounds like someone who raises mages in a cage in their back yard.) "Templar" is a fun word that's very knighty sounding, but it has religious overtones and basically seems like it would be better for a type of paladin. "Legionnaire" is a cool word, but it really emphasizes the organization membership.
Spellblade -- my favorite D&D version of this concept; warriors trained to mix swordplay with spellcasting, who then can work as mercenaries or whatever. Unfortunately, it's not clear from the name why the person is doing this (why not train as full wizards or full fighters?). WotC later released a full-class version of the spellblade called, for some reason, the "Duskblade," but I hate this name because it has nothing to do with anything. "Spellblade" also suffers from being a made-up compound word (we don't call paladins "Holyknights").
Vigilante -- both warriors who learn forbidden arcane magic AND wizards who learn forbidden martial techniques. This has a flavor that I really like a lot because of its implied role in the setting. BUT it implies a lot about the setting which may not otherwise be true (i.e. in most settings there's nothing forbidden about mixing techniques like this).
Dabbler -- this person is self-taught; a scrappy fighter, a magical hacker. I like this flavor a lot too, but the name is weak; nobody really wants to play a "Dabbler" I don't think. It almost calls for an even more generic name, like "Adventurer" or "Hero," but that's no good because it implies other characters aren't those things. "Vigilante" could work for this.
Destined -- in fantasy fiction, often the protagonist starts out learning some swordplay but then discovers that they have an amazing magic power! yay! And I like the idea of a class that is super-rare in the setting, by its very nature. Unfortunately the flavor feels more sorcerer-like, which is fine, except then it's a Charisma half-caster and too similar to the paladin.
Arcanist -- a military position. Any army of sufficient size is going to need specialists to deal with enemy mages; but in a military context, they'll probably become warriors, too. I don't like the name "Arcanist" because it's a made-up word, but, I think it captures well the more pragmatic view of magic. "Thaumaturge" is a fancy word for this, and I like it, but I think it's too much of a mouthful for the average person.
Noble -- I had a setting in which the only people who could afford the time and money to learn both fighting AND wizardry were the nobility. Unfortunately this doesn't fit well in D&D's implied setting, or with the broader fantasy genre featuring fighter-wizards. Plus there's a really rad noble class in EN5ider's Touch of Class. "Scion" and "Patrician" are cool alternate names for this concept, though.
Adept -- based on Shadowrun's adepts, who are warriors that channel magic into their bodies (more like monks, really). I like this name because it implies skill -- the unifying concept of all the above is that this character is highly skilled (not in the 5E sense of "skill proficiencies," but in the broader sense that learning both magic and combat requires you to be a badass.) But, "Adept" is pretty meaningless to the average person. This is probably the least bad option here, because it's the kind of word that could, in time, become a meaningful word in the context of D&D (the way "ranger" and "paladin" and "druid" and "bard" have very specific meanings in D&D that are different than their general meanings).
Arcane Warrior -- some of the above become subclasses: "keeper" is more defensive; "spellblade" is more offensive; "vigilante" is a bit more skilly; "witch hunter" is specialized anti-magic; "gish" is specialized in planar travel. I lean towards this option when I've just given up on finding a one-word name for the class. On the plus side, I firmly believe that you should have a healthy amount of subclass concepts in mind when designing a core class; if the class concept is so narrow that it doesn't support many subclasses, then it's probably a weak class concept.
I'll add a couple to this list:
Vanguard
Luminary
Both carry a connotation of "elite", and Vanguard also essentially means "leading from the front" - something that can definitely be attributed to arcane warriors.
The problem, like with many other gish concepts and names, is that they are also lacking in real-world inspiration of any sort. Granted, so is "fighter", but it sort of has to be.