I must have a prodigious quantity of mind, Mark Twain once wrote. "It takes me as much as a week, sometimes, to make it up." The indecision Twain laments is fairly common; only when inability to make decisions reaches an abnormal level does it have an uncommon name: abulia. The English term we use today comes from a New Latin word that combines the prefix a-, meaning "without," with the Greek word boulē, meaning "will." Abulia can refer to the kind of generalized indecision that makes it impossible to choose what flavor ice cream you want, though it was created to name a severe medical disorder that can render a person nearly inert.
borrowed from New Latin, probably borrowed from Greek aboulía "thoughtlessness, irresolution, indecision," derivative of áboulos "inconsiderate, ill-advised," from a-a- entry 2 + -boulos, adjective derivative of boulḗ "will" — more at boule entry 1
The term was introduced by the German physician Johann Christian August Heinroth (1773-1843), in Lehrbuch der Störungen des Seelenlebens (Leipzig: Vogel, 1818), pt. 1, p. 347: "Formen der dritten Gattung: Willenlosigkeit; ([Greek letters] aboulia) §231 Erste Form: reine Willenlosigkeit (Abulia simplex)" ["Forms of the first variety: will-lessness; (aboulia) §231 First form: pure will-lessness (Abulia simplex)"]. Heinrothʼs citation of the Greek form suggests that he borrowed the word from Ancient Greek, though he could as likely have coined it on his own from the Greek elements, seeing that the word looks like a translation of German Willenlosigkeit.