sharp as a bowling ball

colloquial not-comparable

(simile, colloquial) Not at all sharp-witted; very stupid.

Japanese Meaning

知性に欠ける、非常に馬鹿である

When it came to math, Jeff was sharp as a bowling ball.

数学になると、ジェフはまるでボウリングの球のように全く頭が切れなかった。

Sense（1）

(simile, colloquial) Not at all sharp-witted; very stupid.