How to say "moron" in Japanese

Choosing the right word
  • ばかJLPT N3approx.Common
    nounThe default word for calling someone an idiot, fool, or moron. It is the common, all-purpose choice, usable among friends as teasing or as a genuine rebuke depending on tone.
    こんな荒あれ模様もようの日ひに外出がいしゅつするなんて君きみは馬鹿ばかだよ。↗
    You are an idiot to go out in this weather.
  • nounA derogatory way to call someone a stupid idiot or moron. Being less common, it is not usually the word you want; it works as a colorful, contemptuous put-down.
  • 低能者ていのうしゃ
    nounMatches 'moron' in the sense of a person of low intelligence, closer to 'imbecile'. It directly disparages someone's mental ability and is harsh rather than playful.
  • 馬鹿者ばかもの
    nounA fool or idiot; a somewhat more written-style way to call someone a moron. It conveys the same basic stupidity as ばか but as a noun labeling the person.
    私をばか者しゃだと思おもいますか。↗
    Do you take me for a fool?
  • noun, interjectionA colloquial, derogatory insult like 'goddamn idiot' or 'nitwit'. Use it for angry shouting at someone, not for neutral description; it is stronger and ruder than plain ばか.
    俺おれは人事課じんじかの馬鹿ばか野郎やろうにあごで指図さしずされるつもりはない。↗
    I will not be dictated to by some idiot in the personnel department.

For the basic 'stupid person' sense use 「ばか」; the others add flavors — 「ばかやろう」 is a heated insult, 「すっとこどっこい」 a derogatory put-down, 馬鹿者 a fool, and 低能者 stresses low intelligence.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

Japanese equivalents
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JLPT vocabulary levels are community estimates, not official (no official lists have been published since the 2010 revision).

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