noun
heavy drinker; person who can hold their liquor
Refers to someone who drinks a lot or can drink a lot. Often contrasted with 下戸 (a non-drinker or someone who cannot drink much).
See also: 下戸
彼はかなりの上戸で、毎晩のように飲んでいる。
He's quite a heavy drinker and drinks almost every night.
noun, used as a suffix
... drinker; ... drunk
Suffix attached to words describing a person's drinking habits or behavior when drunk, e.g. 笑い上戸 (a merry drunk who laughs a lot), 泣き上戸 (a maudlin drunk).
彼は笑い上戸で、お酒を飲むとずっと笑っている。
He's a merry drinker and laughs all the time when he drinks.
noun, used as a suffix
liker of; fan; enthusiast; -phile
Ryuukyuu dialect suffix meaning a lover or enthusiast of something, e.g. 泡盛上戸 (awamori lover). Not standard Japanese.
See also: じょーぐー
沖縄では「泡盛上戸」という言い方をする。
In Okinawa, they say 'awamori-jōgo' to mean an awamori lover.
下戸 is the opposite: a non-drinker or someone who cannot drink much, while 上戸 is a heavy drinker.
The historical derivation is uncertain; the kanji 上 (up, above) and 戸 (door) are conventionally associated with the meaning 'drinker', possibly from an old classification system.