Note: This question may contain wordings that may be considered rude to some, so proceed with open mind and caution.

One of the legacies of Japanese colonization in my country during WW2 is a rude slang name-calling word "bagero" which roughly means "stupid bastard", which I could easily map to the similarly sounding colloquial phrase バカヤロウ soon after I started learning Japanese. The people at that time probably could not make out what they heard and simply understood the interjection as "bagero".

However, I am still wondering if the "bagero" version really came from the people mishearing "バカヤロウ", or there was a dialect that really pronounced バカヤロウ as バゲロ. Was there?

There is also a longer version of the localized interjection, "bagero kuntoroyo", that I still cannot decipher until now. Can anyone suggest what would be the original Japanese bad words, if any?

N.B. My purpose of asking this question is not to learn about the bad words, but simply out of curiosity about this phrase that are (fortunately becoming rarely) used by local people here who are oblivious of its actual meaning.

  • 5
    Is that giant warning really necessary? I'm an adult, I can just about cope with "stupid bastard" without breaking into tears.
    – Kdansky
    Jul 29, 2011 at 17:15
  • 2
    Actually, by the time I see the warning, I had already seen バカヤロウ in the title. If a warning is really necessary, you need a warning before the title! :) Jul 29, 2011 at 20:04
  • I guess that "kuntoroyo" may be standing for 「この野郎」 or 「クソ野郎」.
    – vdudouyt
    Dec 7, 2016 at 1:35

2 Answers 2


Searching for bagero bakayaro on Google yielded the following quote, a firsthand account of the time when "bagero" appeared on the scene. It cites "bakayaro" as its source word:

Thursday, March 26, 1942

... And for the first time we heard the word "bagero"[24]...

[24] Bagero = bakayarō, a strong term of abuse frequently used by Japanese soldiers towards the Chinese and others they considered their inferiors. The meaning is something like "you stupid oaf."

(Source: Google Books)

This is from a book called "Prisoners at Kota Cane", a memoir from the perspective of an Indonesian arrested by the Dutch during WWII.

Also, in this page, someone recounts a trip to Burma where he saw a comic skit that mimics a Japanese soldier (circa 2001-2011):

軍帽を被った男がぞんざいな態度で「バッキャロー」と言う。 A man with a military cap says "bakkyarō" in a rude manner.


「バッキャロー」は相手を侮蔑する言葉として、アジア全般に知られた日本語だ。 " bakkyarō" is a well-known Japanese word through out Asia for showing contempt at the other person.

I don't know about the validity of the last sentence, but I conjecture that bagero really came from bakkyarō, an informal version of bakayarō, because they sound more closer.

Regarding kuntoroyo, I couldn't find any reference on the web. Maybe このとろい奴め "You sluggard", or この野郎, as sawa says?


I have no evidence, but I guess what you think is right. This person (be careful with the link; the back button does not work) is saying the same thing. 'Kuntoroyo' sounds close to この野郎 (kono yaroo) 'You bastard!' to me.

  • Apparently I not only can't make edits, I can't fix a spelling mistake with an edit, either. That should be 'bastard'.
    – William
    Jul 29, 2011 at 15:08

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