Many classic definitions are perceived ambiguously. This happens for a whole list of reasons: they are becoming obsolete, because of which contemporaries simply can’t remember the true meaning of a capacious term, they are used out of place, and sometimes - in complete contradiction to the basic meaning! A good example is literacy. This word is often used by teachers, it is deposited in memory, and then repeatedly reproduced at the household level, losing its original meaning.
What is the practice?
An obvious connection with literacy, with the ability to read and write down your thoughts. Once such a science was the privilege of the aristocracy, which could allocate time to educate the child and hire specialists to transfer knowledge. In addition, why are commoners reading and writing, if they spend their whole lives in the field, and the document flow is absent as such? Everything changed when basic information about nature and the world began to be taught in public schools.
Let the quality of education be low, and the skills of a pig or a sloppy shepherd will take advantage of the force a couple of times in your life. But he understands the meaning of the word with a letter, he will be able to read the royal decree or the holy book on occasion. And there he will be beaten out into people, get a job as a servant in the manor house, provide a family!
Just one interpretation?
People lay several meanings in a beautiful term at once, and all of them are associated with elementary skills:
Work with manuscripts was monotonous and required perseverance. Highly respected post. Gradually, the word spread after reading and writing skills, there were more people in the world who could speak not only aloud. Occasionally, the concept under study pointed to some abstract knowledge in the chosen profession, albeit not directly related to books.
What is the problem?
An incredibly positive word that marks the knowledge and skills of the interlocutor. That's just seriously attached to the context and can cause a negative reaction with one of its appearance in the phrase. Why is this happening? Historically, literacy is a good field for irony. They added a little sarcasm, and now recognition of merit from praise turns into a statement of nothing insignificant fact.
And if an inexperienced young man hears the term in this vein, he can perceive it in the sense of antonym. Subsequently, use, meaning "ignoramus", and misleading others. Always try to replenish the vocabulary carefully!