asinine

Roald Dahlの "The Witches" を読んでいます。
"Hello, Dad" Bruno said. He had a silly sort of mousy grin on his face.
Mr Jenkins's mouth dropped open so wide I could see the gold fillings in his back teeth.
"Don't worry, Dad," Bruno went on. "It's not as bad as all that. Just so long as the cat doesn't get me."
"B-B-Bruno!" stammered Mr Jenkins.
"No more school!" said Bruno, grinning a broad and asinine mouse-grin.
"The Witches" は子供向けの物語ですが、結構難しい単語が出てきます。子供がネズミに変えられる章のタイトルは "Metamorphosis" となっていて、今日取り上げる "asinine" も難しい単語に見えます。辞書を見ます。

・Oxford English Dictionary: Extremely stupid or foolish.: Lydia ignored his asinine remark

・Collins Dictionary: If you describe something or someone as asinine, you mean that they are very foolish.

・Cambridge English Dictionary: extremely stupid: an asinine comment