In the words ignominy, ignoble, and words related to ignore, the prefix ig- means not.
Words Related to Lack of Knowledge
Ignorance and its related forms come from the Latin verb ignorare, “not to know.”
Initially the English verb ignore meant “to be ignorant of.” Like “J’ignore” in modern French, “I ignore” meant simply, “I don’t know.”
In modern English ignore means “to refuse to take notice (of).” Ex. “I always smile and say ‘Hello,’ but she ignores me.”
ignorance and ignorant
Both these words relate to the fact or condition of not knowing something. As everyone is born ignorant, no shame should attach to the mere fact of being ignorant. However, the words have acquired negative connotations and both are often used to insult, hurt, or condemn.
For example, when Emilia discovers Desdemona’s dead body, ignorant is one of the terms of abuse she hurls at Othello:
Emilia: Thou has not half that power to do me harm
As I have to be hurt. O gull! O dolt!
As ignorant as dirt! thou hast done a deed–
I care not for thy sword; I’ll make thee known,
Though I lost twenty lives. –Othello, ii, 192-195.
Ignoramus [IG-nuh-RAY-mus] was an earlier generation’s favorite word for an ignorant person. For example, “That ignoramus doesn’t know the difference between imply and infer.” In fact, ignoramus is plural in origin. It’s the second person plural of the Latin verb ignorare: ignoramus, “we do not know.” It was a legal term:
ignoramus: The endorsement formerly made by a Grand Jury upon a bill or indictment presented to them, when they considered the evidence for the prosecution insufficient to warrant the case going to a petty jury.
I think the word dummy has probably replaced ignoramus in modern usage.
Words Related to Lack of Reputation
The etymology of both ignominy and ignoble can be traced to the Latin word for name.
Etymologically, ignominy [IG-nuh-MIN-ee] is the state of not having a name.
Roman culture, like many others, attached great importance to the sanctity of the family name. Name and reputation were synonymous. Although he puts the words in the mouth of that toad Iago, Shakespeare expresses the importance of reputation in this speech from Othello:
Good name in man and woman, dear my lord,
Is the immediate jewel of their souls:
Who steals my purse steals trash; ’tis something, nothing;
‘Twas mine, ’tis his, and has been slave to thousands:
But he that filches from me my good name
Robs me of that which not enriches him
And makes me poor indeed. –Othello, III, iii, 156-161
A disgraced name is a name lost. The meaning of ignominy, therefore, is “dishonor, disgrace, shame, infamy.”
The adjective is ignominious [IG-nuh-MIN-ee-us]
Like ignominy, ignoble has connections with reputation–or lack of it.
The word noble goes back to Latin nōscere, “to know.” The best-known people were members of the ruling classes. Their families had the wealth to buy the horses, weapons, and armor that enabled them to make a name for themselves. Being “known” conferred status. The word for being known became a class marker. Noble began as a word that referred to a social and economic class, but gradually acquired additional meanings.
Initially, ignoble meant “not noble,” that is, not born to the noble social class. Because the privileged class saw itself as superior in every way, noble came to mean “characterized by moral superiority,” and ignoble came to mean “morally flawed”:
A rake is a composition of all the lowest, most ignoble, degrading, and shameful vices; they all conspire to disgrace his character, and to ruin his fortune. –Philip Dormer Stanhope 4th Earl of Chesterfield (1694–1773)