Etymology
Advertisement
ignorant (adj.)
late 14c., "lacking wisdom or knowledge; unaware," from Old French ignorant (14c.), from Latin ignorantem (nominative ignorans) "not knowing, ignorant," 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" (source also of Classical Latin noscere "to know," notus "known"), from Proto-Latin suffixed form *gno-ro-, suffixed form of PIE root *gno- "to know." Also see uncouth.

Form influenced by related Latin ignotus "unknown, strange, unrecognized, unfamiliar." Colloquial sense of "ill-mannered, uncouth, knowing nothing of good manners" attested by 1886. As a noun, "ignorant person," from mid-15c. Related: Ignorantly.
Related entries & more 
Advertisement
ignorance (n.)

c. 1200, "lack of wisdom or knowledge," from Old French ignorance (12c.), from Latin ignorantia "want of knowledge" (see ignorant). Ignoration (1832) has been used in the sense "act of ignoring." The proverb, in the form "Where ignorance is bliss, 'tis folly to be wise", is from Gray's "Ode on a Distant Prospect of Eton College" (1742) .

Related entries & more 
ignore (v.)
1610s, "not to know, to be ignorant of," from French ignorer "be unaware of" (14c.), or directly from Latin ignorare "not to know, be unacquainted; take no notice of, disregard" (see ignorant). The original sense in English is obsolete. Sense of "pass over without notice, pay no attention to" in English first recorded 1801 (Barnhart says "probably a dictionary word"), and OED indicates it was uncommon before c. 1850. Related: Ignored; ignoring.
Related entries & more 
ignoramus (n.)
1570s, originally an Anglo-French legal term (early 15c.), from Latin ignoramus "we take no notice of, we do not know," first person plural present indicative of ignorare "not to know, take no notice of" (see ignorant). The legal term was one a grand jury could write on a bill when it considered the prosecution's evidence insufficient. Sense of "ignorant person" (1616) came from the title role in George Ruggle's 1615 play in Latin satirizing the ignorance of common lawyers. The plural is ignoramuses as it never was a noun in Latin.
Related entries & more 
*gno- 

*gnō-, Proto-Indo-European root meaning "to know."

It forms all or part of: acknowledge; acquaint; agnostic; anagnorisis; astrognosy; can (v.1) "have power to, be able;" cognition; cognizance; con (n.2) "study;" connoisseur; could; couth; cunning; diagnosis; ennoble; gnome; (n.2) "short, pithy statement of general truth;" gnomic; gnomon; gnosis; gnostic; Gnostic; ignoble; ignorant; ignore; incognito; ken (n.1) "cognizance, intellectual view;" kenning; kith; know; knowledge; narrate; narration; nobility; noble; notice; notify; notion; notorious; physiognomy; prognosis; quaint; recognize; reconnaissance; reconnoiter; uncouth; Zend.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit jna- "know;" Avestan zainti- "knowledge," Old Persian xšnasatiy "he shall know;" Old Church Slavonic znati "recognizes," Russian znat "to know;" Latin gnoscere "get to know," nobilis "known, famous, noble;" Greek gignōskein "to know," gnōtos "known," gnōsis "knowledge, inquiry;" Old Irish gnath "known;" German kennen "to know," Gothic kannjan "to make known."

Related entries & more 
Advertisement
nescient (adj.)

early 15c., nesciant, "ignorant; unwilling," from Latin nescientem (nominative nesciens) "ignorant, unaware," present participle of nescire "not to know, to be ignorant," from ne "not" (from PIE root *ne- "not") + scire "to know" (see science).

Related entries & more 
nescience (n.)

"ignorance, a state of not knowing," 1610s, from Late Latin nescientia, from Latin nesciens "ignorant, unaware," present participle of nescire "not to know, to be ignorant," from ne "not" (from PIE root *ne- "not") + scire "to know" (see science).

Related entries & more 
bonehead (n.)

"stupid person," 1908, from bone (n.) + head (n.). Compare blockhead, meathead. Bone-headed "ignorant" is from 1903. Earlier it was used in reference to types of primitive spears or harpoons.

Related entries & more 
unlearned (adj.)
c. 1400, "ignorant," from un- (1) "not" + learned (adj.). From 1530s as "not acquired by learning," from past participle of learn (v.). Old English had unlæred.
Related entries & more 
uninformed (adj.)
1590s, from un- (1) "not" + past participle of inform. Originally in reference to some specific matter or subject; general sense of "uneducated, ignorant" is recorded from 1640s.
Related entries & more