The story
From Oblomov + -ism, after the nobleman who rarely leaves his bed in Ivan Goncharov's novel Oblomov (1859). The term is the common English translation of the Russian term обломовщина (oblomovščina), coined by Nikolay Dobrolyubov in an essay on that novel entitled «Что такое обломовщина?» (“What is Oblomovism?”), also published in 1859.
Etymology from Wiktionary, CC BY-SA 4.0.