I found your queries quite intriguing because I have to admit that I’d never considered the structure of the title – as long as I could understand it, that was all that mattered – and so I had to do a little research. I’ll address your questions one by one, but only after breaking down the title myself, because I think there are some things you’re not aware of (and which I’ve frankly only just discovered) that are preventing you from parsing it:
The fact that からかい上手 is written like that, as one word, suggests that it’s a compound. However, I don’t think it’s very common, so it’s not surprising that it’s confusing. Either way though, if we look at this on a very superficial level and try to use facts about typical Japanese syntax to look for clues, we’ll see that this phrase is basically AのB, and we know for certain that B is a noun. Typically, in this case, A is a noun or what some people call a の-adjective (e.g. ふつう, for ‘normal’ or ‘ordinary’). However, when A is this long and clearly can be broken down into smaller parts, I’d say it’s fairly likely that it’s a noun. Still, maybe I’m wrong, so what does the dictionary say?
If you look up 上手 in a monolingual dictionary, you’ll see that, among the examples, there are phrases like 聞き上手 or 話し上手. Clearly (if you’re familiar with Japanese verbs), the structure of these words is ‘masu-stem + 上手’. If you look at the definitions of those words, you’ll see that they refer to skill in asking (聞き上手) or speaking (話し上手), and that in grammatical terms, they can be used as both な-adjectives and nouns. (Being a な-adjective also means that it can be used adverbially with に, but since we can just consider that as a feature of な-adjectives, I’m not going to add another classification just for that.) As adjectives, they mean ‘skilful in ~’, and as nouns, they refer to people who are skilful in the act expressed by the verb form.
Let’s come back to the title we’re looking at. Based on what we’ve just seen, からかい上手 would refer to ‘skill in teasing’, and can be used as an adjective (‘skilled at teasing’) or a noun (‘a skilled teaser’). The question then is… which interpretation fits best here? Since の is being used, and not な, I guess it’s reasonable to assume that the noun interpretation is the correct one. However, most of us start off learning の as the ‘possession particle’, the ‘inverted “of”’ or the particle allowing a noun to modify a noun, so you might be wondering how that makes any sense.
To answer that, let’s look at the English translation of the title: ‘Teasing Master Takagi-san’. Notice how there’s no sign of anything like ‘of’, possession or the usual sort of noun-noun modification we see in compound nouns (e.g. oil bottle = a bottle containing oil or meant to contain oil). Funny thing though: a ‘teasing master’ would be pretty skilled at teasing, so that matches the noun definition of からかい上手 perfectly. What’s の doing in the title then? It’s the appositional の, which I think you’re aware of based on your fourth question, but I figured I’d cover it just to be sure. Here, からかい上手 and 高木さん both refer to the same person, and の simply connects them, with 高木さん being the main noun nonetheless. In short, this is why the English translation is the way it is.
Now then, some direct answers to your questions:
- As we just saw, からかい上手 is a sort of compound adjective/noun composed of a verb form and an adjective. More common examples of such structures (masu-stem + adjective) include 〜やすい、〜がたい、〜づらい and so on (e.g. you may have seen わかりやすい for ‘easy to understand’ at some point).
- This isn’t how this particular example works, as we just saw, but so, if we’re talking about the difference between the adjectival usage of からかい上手 and the noun usage, the answer is yes, you would use な, but no, the meaning wouldn’t be exactly the same. With な, one describes a characteristic and makes it sound inherent; With の, one labels something and puts it in a particular category. That’s the difference. If you want, Tofugu wrote an excellent article about it, with lots of examples:
The Guide to Na-Adjectives and "So-Called" No-Adjectives
- Because it’s a special structure (see Answer 1 and what I said earlier).
- Yes, your translation would also work, except that ‘joker’ is not the right word here because からかう is about messing with someone else and having fun doing so. Like I said though, we’re really looking at a compound な-adjective that also functions as a noun, so in Japanese, it’s [big compound noun]の[name], but in English, we’d have to find some way to explain the meaning of the compound noun. As we’ve seen with the official title translation though, it can indeed be done with nouns alone, and in a fashion very similar to the original title’s structure:
Teasing Master Takagi-san
[verb form] [noun] apposition [noun]