A tool (hammer) used for driving nails or striking objects; a hammer with a heavy head and a handle.
棚を組み立てるときに金槌が必要だ。
You need a hammer when assembling the shelf.
大工はいつも金槌を腰に下げている。
The carpenter always hangs a hammer at his waist.
釘を打つときは金槌の中心で打つと安定する。
When driving a nail, hitting with the center of the hammer gives more stability.
A colloquial term for a person who cannot swim or is extremely poor at swimming (often written in kana: かなづち).
子どものころからの友達は完璧なかなづちだ。
My childhood friend has always been a complete non-swimmer.
海に入るときは、かなづちの人が無理をしないよう気をつけてください。
Be careful not to push people who can't swim when entering the sea.
彼は水に浮けないほどのかなづちだが、ライフジャケットがあれば安心だ。
He's such a poor swimmer that he can't float, but he's safe with a life jacket.