One of the ultra-fascinating facets of Japanese is its super-large arsenal of intensifying prefixes that provide an otherwise neutral expression with some emphatic edge. The best-known (and least spectacular) of them is dai (大), which usually translates as “big.” When something went really well, for instance, people call it dai-seikō (大成功, big success), whereas in the opposite case they acknowledge dai-shippai (大失敗, big failure). The trick works not only with Sino-Japanese words but also with native Japanese vocabulary. In such cases, the character usually takes its kun-reading, ō. Some examples are ō-yorokobi (大喜び, big delight), ō-machigai (大間違い, big mistake) and ō-sawagi (大騒ぎ, big fuss). Exceptions to this reading rule of thumb are ō-sōji (大掃除, big end-of-the-year house cleaning)and ō-genka (大喧嘩, big quarrel), where despite the Sino-Japanese main word the prefix reads ō rather than dai. The reverse combination is also possible, as in the antonym pair dai-suki (大好き, love) and dai-kirai (大嫌い, hate).
If something is more than just big, the superlative prefix sai (最) is there to express it. Accordingly, something can be sai-kōkyū (最高級, highest class) or sai-kai (最下位, lowest rank). In more casual language, the prefix can be frequently spotted in expressions such as sai-kō (最高, best), sai-tei (最低, outrageous), and sai-aku (最悪, the worst that could happen).
If that still isn’t enough emphasis, you can always rely on chō (超). Just like its English correspondent “super,” this prefix used to be confined to a handful of technical terms such as chō-onpa (超音波, supersonic) or chō-kōsoku (超光速, superluminal). Not so in present-day Japanese, where it can be attached to almost everything, from chō-ninki (超人気, hyper-popular) and chō-kawaii (超可愛い, super-cute) to chō-mukatsuku (超むかつく, to be super irritated) and chō-arienai (超ありえない, un-freaking-believable). The prefix also comes in handy when superlatives like those described in the previous paragraph need further upgrade. If something is better than the best, just call it chō-saikō (超最高); if someone behaves worse than worst, chō-saitei (超最低) is the word for it.
While chō pairs up with almost everything, there are a couple of other intensifying prefixes whose usage is largely restricted to a few specific words. When there is some sort of excess, the intensifier ka (過) can be an option, as in ka-hōwa (過飽和, oversaturation) ka-hogo (過保護, overprotection), and ka-hoshō (過補償, overcompensation). In other cases, the prefix mō (猛) is used to create a similar effect. Examples are mō-supīdo (drive with insane speed), mō-benkyō (猛勉強, study like crazy) and mō-hantai (猛反対, be dead against). Also good to know, particularly around this time of year, is mō-sho (猛暑, scorching heat).
Two other intensifiers with an ultra-limited vocabulary range are goku (極) and geki (激). The first one can be found in goku-futsū (極普通, extraordinarily ordinary), goku-usu (極薄, ultra-thin) and goku-uma (極旨, mega-yummy). The second is most to be seen in the two terms geki-yasu (激安, super-cheap) and geki-kara (激辛, extra-spicy), usually with an exclamation mark for further emphasis.
Yet another intensifier with a rather narrow productive range is ma (真). It literally translates as “truly” and tends to team up with spatial or temporal expressions, as in massugu (真っ直ぐ, straight forward), mannaka (真ん中, right in the middle), ma-gyaku (真逆, exactly the other way round), mappiruma (真っ昼間, in broad daylight) and ma-yonaka (真夜中, at dead of night). Here, too, further upgrade is possible, with another super-fascinating little prefix: do (ど or ド). For example, when something is even more in the middle than just right in the middle (whatever place that might be), it is do-mannaka (ど真ん中). Other possible combinations are do-inaka (ど田舎, hyper-rural), do-konjō (ど根性, to have [more than] a lot of guts), do-hakuryoku (ド迫力, super-powerful, as the pachinko machines advertised in the photo), as well as どM and どS, which stand for two complementary sexual preferences.
One final mega-intensive intensifier that needs to be mentioned is baka. As the term literally means “idiot,” it is most commonly used for negative statements. When something is baka-takai (バカ高い), for instance, you consider it ridiculously expensive (though the opposite, baka-yasui [バカ安い], is also possible). Two other examples are baka-majime (バカ真面目, excessively serious) and baka-shōjiki (バカ正直, alarmingly honest). Incidentally, the term baka also has its own adjective, bakabakashii (absurd, nonsense). So, if you find all this super-superlative talk entirely pointless and totally hyper-idiotic, here is my suggestion of what you could call it: baka-bakabakashii (バカばかばかしい).