It’s a proper noun(固有名詞), or coined word, so there is no meaning or best way to translate it.
The title was originally supposed to be 幽遊記 (Yuyuki), which was inspired by 西遊記 (Saiyuki). Is Saiyuki not supposed to be translated, either?
西 = West
遊 = Journey, Travel, Wander, Visit, going somewhere, etc (it could also mean "coming from somewhere")
記 = Record
So, it literally means "record of going to the west", but it's usually just called "Journey to the West" in English. Is it incorrect to translate Saiyuki as Journey to the West because it's a proper noun or whatever? Even though everyone calls it Journey to the West?
At best, you’ll have to look at each Kanji
or dissect the name into several parts to assume or interpret what it means.
the 白書 Hakusho part of the name is supposedly based on White paper, an official publication of a government newspaper, or news report.
Supposedly? 白書 (Hakusho) literally means "white paper" in Japanese, which is what they use for government reports, files, documents, records, etc. I thought you were a native speaker fammy fam
I'm pretty sure Togashi didn't intend for the title to be unintelligible gibberish in Japanese. There are obvious connotations that tell us what the intended meaning is, even if it doesn't come out as catchy in English. Frankly, "Yu Yu Hakusho" is as weeaboo of a title as it gets lmao. Any English viewer is gonna be confused as to what the fuck it means. I remember when some people thought it was supposed to be "Yu Yu Haku
Show" lol. If you dub a series then translate the title so they understand it
幽遊(Yu Yu) is just 2 kanjis straddled
together in order, there is no word or actual meaning for it in the dictionary.
You’ll have to dissect it into 2 parts for each kanji.
幽 = Dark, hidden, gloomy, underworld, netherworld, etc.
There's definitely a "ghost" or "spirit" connotation that Togashi went for. Ghosts and spirits are hidden in the dark and come from the underworld/netherworld. Unsurprisingly, they're a big focus in the series.
遊 can mean "play" in Japanese but it also means journey, travel, wander, visit, going somewhere, etc as I said before. From what I've gathered, it mainly means "play" in Japanese and "traveling", "wandering", etc in Chinese. While Yu Yu Hakusho is a Japanese series, its title evolved from Yuyuki, which was based on Saiyuki, the Japanese name for the Chinese story "Journey to the West".
Yusuke becomes a wandering ghost, or spirit, at the start of the series so I don't think this is coincidental. Would the title more accurately mean something like "report on wandering ghosts"? Or "report on visitations from the underworld"? Or "Underworld Visitor Report" ? "Hidden Visitor Report"? "Wandering Ghost Files"?
Also, I have seen the theory that the two Yu's are short for 幽霊 遊猟 (Yurei Yuryo). The title Yu Yu Hakusho is stylized as is stylized as 幽☆遊☆白書; those stars are supposedly supposed to represent abbreviated kanji. Apparently that's a common thing in Japanese.
幽霊 (Yurei) means ghost. 遊猟 (Yuryo) means "recreational hunting". If it's true that Yu Yu Hakusho is short for those words, then wouldn't the title be something like "Ghost Hunting Report" in English? It would make sense since Yusuke is called a Spirit Detective in the series and he hunts stuff like ghosts.
Fun facts: The subtitle for the 1998 English localization of one of the movies was "Poltergeist Report". The subtitle for the 2000s Funimation dub was "Ghost Files". The Filipino dub localized the title as "Ghost Fighter".
All of these would have been better titles than weeb ass "Yuyu Hakusho" huehue