Origin of ignorant
An interesting use of ignorant appears in Mark Twain’s “Old Times on the Mississippi,” an essay he wrote for The Atlantic Monthly in 1875 and that was later incorporated into chapter 4 of Life on the Mississippi (1883): “This fellow had money, too, and hair oil. Also an ignorant silver watch and a showy brass watch chain.” By transferring the “lacking in knowledge” sense of ignorant from human beings to an object, the ever-clever Twain beautifully and succinctly described a timepiece that doesn’t tell the correct time.
British Dictionary definitions for self-ignorant
Word Origin and History for self-ignorant
late 14c., from Old French ignorant (14c.), from Latin ignorantia, from ignorantem (nominative ignorans), present participle of ignorare "not to know, to be unacquainted; mistake, misunderstand; take no notice of, pay no attention to," from assimilated form of in- "not, opposite of" (see in- (1)) + Old Latin gnarus "aware, acquainted with" (cf. Classical Latin noscere "to know," notus "known"), from Proto-Latin suffixed form *gno-ro-, related to gnoscere "to know" (see know).
Form influenced by Latin ignotus "unknown." Cf. also uncouth. Colloquial sense of "ill-mannered" first attested 1886. As a noun meaning "ignorant person" from mid-15c.