Translation guide
The English phrase "fast liver" is an archaic or literary term for a person who lives a dissipated, pleasure-seeking, or morally loose life. In Japanese, there is no direct equivalent, but several words and phrases capture the idea of a debauched or profligate person.
To describe someone who indulges in drinking, partying, and loose living, often with a connotation of moral laxity.
A person who leads a debauched or dissipated life; a libertine. This is the closest general term.
彼は若い頃、放蕩者として知られていた。
He was known as a fast liver in his youth.
A person devoted to pleasure, often implying a spendthrift or someone who neglects responsibilities for enjoyment.
A playboy or pleasure-seeker; often used for someone who spends time and money on entertainment and women.
A dissolute or self-indulgent person; emphasizes moral decay and lack of self-discipline.
自堕落者だった彼は、ついに身を持ち崩した。
As a fast liver, he eventually ruined himself.
Do not translate "fast liver" literally as 速い肝臓 (はやい かんぞう). It has no meaning in Japanese and will cause confusion.
That fast liver squandered his fortune.
彼は遊び人で、夜な夜な街に繰り出している。
He's a fast liver, going out on the town night after night.