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idiot; moron; fool
stupid; foolish; dull; absurd; ridiculous
trivial; insignificant; disappointing
malfunctioning; defective; losing sensation
incredibly; unusually; exceptionally
fervent enthusiast; nut; person singularly obsessed with something
Mactra chinensis (species of trough shell)
彼は馬鹿ではないと私は思う。
I don't think he's a fool.
馬鹿なことを言わないでちゃんとして。
Don't say foolish things.
自分が馬鹿だったと反省した。
I reflected that I had been foolish.