noun
sledgehammer
A heavy hammer with a long handle, used for striking or driving stakes. The kanji 玄翁 is the most common spelling.
大工さんが玄翁で杭を打ち込んでいる。
The carpenter is driving a stake with a sledgehammer.
The origin is uncertain. The spelling 玄翁 may be ateji, possibly from a proper name or a phonetic assignment. The word is a native Japanese term for a large hammer.