also: うらぼん
noun
under-the-counter porn magazine; uncensored adult magazine
Refers to illegally sold or underground pornographic magazines, typically featuring uncensored photographs. The term carries a strong connotation of illicit distribution.
昔、裏本は繁華街の怪しい店で売られていた。
In the past, under-the-counter porn mags were sold at shady shops in entertainment districts.
彼は裏本を隠し持っているところを見つかった。
He was caught hiding an uncensored adult magazine.
Compound of 裏 (ura, 'back', 'reverse', 'hidden') and 本 (hon, 'book'), literally 'back book' or 'hidden book', referring to its illicit, underground nature.