sharp as a tack

Adjective

colloquial not-comparable

(simile, colloquial) very intelligent

Japanese Meaning

非常に賢い / とても知性に富んでいる

My grandmother is sharp as a tack, remembering everyone's birthday without a list.

私の祖母は頭の切れる人で、メモを取らなくても皆の誕生日を覚えています。

Sense（1）

(simile, colloquial) very intelligent

When Mum died at ninety she was still as sharp as a tack. Everything else wore out.