Ever since the first few episodes of Boku no Hero Academia (My Hero Academia), we could observe the lousy relationship between Kacchan (Bakugo) and Midoriya.
As a part of this bad relationship, Kacchan mockingly dubs Midoriya “Deku”. But why? This is where many posts on the Internet get confused.
Midoriya Izuki name’s meaning
In Japanese, the name of Midoriya Izuku is written 緑谷 出 久.
But, the kanji (Japanese characters) have more than one reading so 出(izu), and 久(ku), the kanji that make up the surname of Midoriya can have multiple pronunciations.
Bakugo & Deku
In one episode, when Bakugo is reading Midoriya’s surname, he tells him that his last name can also be read as “Deku”.
And yes, “de” is another reading of the kanji 出.
So, according to Katsuki (Bakugo), instead of
出 (izu) 久 (ku)
The pronunciation of Midoriya’s last name is:
出 (de) 久 (ku)
Thus, is Deku a derogatory term?
No, but Kacchan uses it as an abbreviation of the word Dekunobou whose meaning is “good for nothing” or in the exact words of Kacchan “someone who can’t do anything.”
Midoriya & Ochaco
Being an insulting word, why does Deku choose it as his superhero name?
“I didn’t like this name until now, but someone changed the meaning of it, and that had a huge impact of it. It made me really happy.” – Midoriya
He was referring to Ochako Uraraka (a.k.a Uravity). In an episode, she said to Midoriya,
“But Deku gives off a feeling of “I can do it.” I like the nickname.”
Wait, but doesn’t “Deku” refer to someone who can’t do anything?
Yes, but it can also be the abbreviation of the word dekiru which is the Japanese verb that you use express ability to be able to do something (i.e. can, or be able to).
For example :
私 は 日本語 が で き る
Watashi wa nihongo ga dekiru
I can speak Japanese.
Using this, Uraraka relates the word deku with the ability to do something.
In other words, Deku means that Midoriya is able to do anything.
Although in Japanese the term deku in it of itself has NO meaning (so don’t try and use it because nobody will understand you) in Boku No Hero Academia the phrase is an abbreviation of the words Dekunobou and Dekiru.
To sum it up
Dekunobou -> Deku: the one who can’t achieve/do anything.
Dekiru -> Deku: the one who can achieve/do anything.
I confirmed all of the above with my Japanese friends.
Btw, Boku No Hero Academia Season 4 is coming out in October 2019!
Here is the trailer: