In politics, war, and other partisan conflicts, “defecting” means abandoning one’s allegiance to join the other side. Someone speaking the word—an action verb in this case—would place emphasis on the second syllable, like this: de-FECT.
If a speaker places emphasis on the first syllable, “defect” is no longer an action but a noun (not an action, but instead a person, place, or thing).
Pronounced DE-fect, the same word means an imperfection—usually one that causes something to be unable to do what it is supposed to do.
“Defect” is an example of how a simple change in inflection can change the nature of something. That’s where the metaphorical term “point of inflection” comes from. “Point of inflection” or “inflection point” is a term that can be used for describing where, when, or how something changes its state.
“Inflection point” is also used in mathematics, to describe the point at which something changes its nature—for example the point at which the curve of a line changes direction and goes from being concave to being convex, or where a trend that is arcing away from what is desired turns to become a trend arcing toward.
When manufacturers recall a product, the news tells us the reason for the recall by describing a “defect” in the product. That’s to tell the public why that product is not performing as it was meant to (and sometimes to explain why it is dangerous to keep using).
Now try practicing inflection by pronouncing this sentence correctly:
“One way a political rebel can rebel is to defect while he is still a member of his party—using his membership to expose the party’s defects.”