Ahojikara replaces bakajikara (chikara is physical strength or power; euphonically changed to jikara) to mean excessively strong. This expression is used in the common phrase kajiba no bakajikara (unusual strength shown in an emergency such as a fire). You can replace bakajikara with kuso jikara.
Ahō has two variations, namely ahodara and ahondara. They are both compound words made from ahō and tara, and are more emphatic than ahō.
Antonyms for baka and ahō also show regional variations. Tokyoites say rikō mono (clever person), while Osaka people use kashikoi and kashikoi hito. When praising a child, Tokyoites will say o-rikō-san or ii ko ne, while people from Osaka say kashikoi ne or ēkoya.
There are a number of other near synonyms for baka that can be used when referring to perceived mental defects or personality shortcomings. Their usage is not as broad as baka or ahō, as they are usually descriptive of a particular, rather than a general, condition.
Saitei, for example, means the lowest, meanest, stupidest. Saitei-na yatsu (or yarō) can be translated as he's an asshole. The term can also be applied to inanimate objects, so that saitei-na koto becomes what shit or what crap.
Teinō, on the other hand, means a half-wit or bone-head, and can only be used when referring to a person, as in kare wa teinō da or mattaku teinō-na yatsu da (he's a total dimwit).
Nōtarin is a simpleton or jerk (nō is brain, and tarin is short for tarinai, which means lacking or insufficient). This is never used as an adjective, and only in connection with a person, as in aitsu wa nōtarin da (he's a jerk). Hakuchi (idiot) is used likewise, but is regarded as discriminatory. Use with care.
Manuke is another synonym for baka. The kanji for ma can also be pronounced aida, and here means a pause between rhythms or actions in Japanese music or dance. Nuke comes from the verb nukeru (to miss or lack). Manuke (without modulation), then, signifies a person who somehow lacks a normal sense of what he's doing, a half-wit or dunce. This word can be used both as a noun and an adjective. Thus, kare wa manuke or manuke-na yatsu or, in a slight variation, kare wa nukete iru, are all common expressions to mean he's out of it.
Hema and doji are close synonyms of manuke. Both can be translated as blunder, bungle, or mess. Doji is an abbreviated form of doshikujiri, from the verb shikujiru (to make a mistake or fail), with the emphatic prefix do-.
Hema is thought to derive from beta (incompetent) and manuke; hecho is its slang variation. Thus, when a person makes a careless blunder, like walking through a puddle instead of around it, you might say hema, manuke or baka, doji. Used as verbs (hema o shita or doji o funda), they can be translated as he goofed.
In English, people are sometimes called stupid jerks. They are in Japanese as well, using the expression tonma. The ma in tonma, which is both a noun and adjective meaning nincompoop, ass, or dimwit, is written with the Chinese character for ass or horse. Tonma da kara muri wa nai, then, means he's such a dunce, I'm not surprised he did something so stupid.
Ton-chiki and ton-chin-kan are two humorous synonyms for tonma. Ton-chiki (dope) can be used only when referring to a person, while ton-chin-kan (absurd, incoherent, or irrelevant) can be applied to people or things. The ton in the latter word comes from ton-tenkan, the sound made by blacksmiths when they hammer in concert with each other. The chin sound signifies being out of sync with others; thus, ton-chin-kan acquired its sense of discordance. Both of these terms can be used by women as well as men.
Noroma comes from noroi, meaning slow or tardy, and it is used to describe someone who is dull or muddleheaded. Again, it can be used as a noun or adjective as in noroma-na hito or aitsu wa baka de noroma (he's a stupid blockhead). Noro-noro suru na (or noro-noro shinai de when used by women) means don't be slow.
Guzu-guzu is an onomatopoetic expression that is a close synonym. It has the added implication not only of slow, but irresolute. Thus guzu-guzu suru na (or shinai de) means stop your dilly-dallying. The guzu from guzuguzu can also be used in place of noroma. Kare wa guzu da means he's a laggard. For emphasis one can say guzu de noroma. Or to be more slangy, use guzura instead of guzu.
Otanchin and anpontan are near synonyms for baka, manuke, and tonma, but their sounds give them a more humorous and colloquial slant. Both of them can be used simply by themselves or in a phrase such as ano otanchin (that boob). For greater effect and emphasis, pronounce it ottanchin.
Otanko-nasu and boke-nasu are similar to otanchin, but have stronger meanings. Nasu means eggplant. Boke here comes from hbkeru or bokeru, which mean to become senile or absent-minded. Literal translations aside, the image should be clear. Grammatically these two words are used in the same way as otanchin and, when used by a woman, should be followed by ne or yo.
Another word that makes use of the explosive "b" sound (as in baka) is bon-kura (blockhead). It comes from yakuza (gangster) language. Bon is the tray on which the mobsters gamble with dice, and kura comes from kurai, meaning dark or without knowledge. The implication therefore is a gambler who knows little about gambling—despite its being his own occupation. In this way, the expression came to mean a useless person.
Dekunobo is a similar word, a very expressive one, meaning blockhead, dummy or dolt, a person who just doesn't react. Deku is a wooden doll or puppet, and bo is an affectionate term for a man. Ano hito wa dekunobo, then, refers to a man who's a dummy or useless.
Pa is really the ultimate put-down. Used in conjunction with a simultaneous upward thrusting, opening gesture of the palm of the hand by the side of the speaker's head, it means a complete dud, a zero, a nothing.
Dame, meaning no good, is probably a word many students of Japanese are already familiar with. But let's look at some of its colloquial applications. A long-running Japanese comic strip was entitled Dame Oyaji (oyaji means father), and the protagonist (if we can call him that) was a helpless, hapless father. Perhaps because of this connection, it's more fashionable and sophisticated to say dame oyaji than the conventional and grammatical dame-na oyaji. The same can be said for dame otoko (man) or dame onna (woman).
Dame has its origins in the Japanese board game of go, in which players compete to secure spaces which then count as their territory. In most cases, useless spaces (muda-na me) will remain in the border areas when the game is over. These spaces are called dame. Aside from this rather specialized use of the word, dame nowadays is applied to anything that is useless, no good, or impossible. Dame-na musuko is an oft-heard lament when parents describe a no-good (or perceived as no-good) son. Deki ga warui ko is similar, meaning an unaccomplished child, while deki sokonai is even worse, literally a failure.
Kono tokei (this watch) wa dame desu means this watch doesn't run or, depending on the context, this watch won't do. Naitemo (even if you cry) dame da means it's useless to cry. When a Japanese mother says simply dame to her child, it means don't do that or, more emphatically, stop it. If you reply dame (desu) when you're asked to do something, it means that you are unable to help out, or simply, no. This can sound a bit abrupt in Japanese, however. A more common and more polite response would be muzukashii (desu), muzukashii being an ordinary word for difficult.
Gūtara is similar to dame in meaning good-for-nothing. Gūtara oyaji can be used almost interchangeably with dame oyaji, and conjures up the image of Dagwood from the comic strip Blondie, relentlessly sleeping on the sofa while the lawnmower languishes in the garage.
Ikare ponchi, now archaic, 13 similar to dame otoko/ onna. The verb ikareru means to become useless or touched in the head. It can be used similarly to dame as in kono tokei wa ikarete iru (this watch doesn't work). Ponchi comes from bonchi (a young boy in Kansai dialect), and ikare is a shortened form of ikareta, the past tense of ikareru. The word became popular after World War II, when traditional Japanese ways of thinking were changing drastically, and many young people became ikare ponchi in their confusion as to how to adjust to the new (dis)order.
Ikareta is still used and by itself means dame in the sense of someone having a hole in his head or being really off his rocker. It can also be used to mean enchanted with as in kare wa kanojo ni ikareteru