helluo librorum

Learned borrowing from Late Latin helluō librōrum (“glutton of books”), from Latin helluō (“glutton; squanderer”) + librōrum (“of books”). Helluō is derived from helluārī + -ō (suffix forming masculine agent nouns, nicknames, and other designations); helluārī is the present active infinitive of helluor (“to be a glutton, gormandize”), further etymology unknown. Librōrum is the genitive plural form of liber (“book; inner bark of a tree”), ultimately from Proto-Indo-European *lewbʰ- (“to cut off, peel”)). The plural form is also borrowed from Late Latin helluōnēs librōrum.

来源：wiktionary