noun
extremely heavy drinker; insatiable drinker
Rare term for someone who drinks without limit, as if their capacity has no bottom. The kanji 底抜け means 'bottomless' and 上戸 is an old word for a drinker.
彼は底抜け上戸で、一晩で一升瓶を空けてしまう。
He is a bottomless drinker and empties a whole 1.8-liter bottle in one night.
Compound of 底抜け (そこぬけ, 'bottomless') and 上戸 (じょうご, 'drinker'). The exact historical derivation is uncertain, but the word is a rare, vivid expression for an insatiable drinker.