In English, to overthrow means to bring about downfall or destruction. The Greek word, anatrepō, which is used in this passage, means the same.
It is unfortunate that Bible commentators mitigate the "destruction" spoken of in this passage by adding the word “figuratively” in their definitions the word, anatrepō.
Holding fast the Faithful Word as he has been taught that he may be able by sound doctrine both to exhort and to convince the gainsayers For there are many unruly and vain talkers and deceivers specially they of the circumcision Whose mouths must be stopped who overthrow [anatrepō] entire households  2 Timothy 3:6 teaching things which they ought not for filthy lucre's sake
 There is nothing figurative about an eternity of destruction that results from being spiritually overthrown. And Paul says this is what is being done by false teachers, whose primary goal is to financially sack their victims.
Victims are plundered both spiritually and financially through deceit and greed. They are financially overthrown when income streams or wealth is funneled to false teachers or when they liquidate and turn their entire net worth over to these wolves.
Contending for the faith is serious business.
The motivation of false teachers is generally greed, and they prey on either legitimate needs of their victims or on their victim’s sins or weaknesses. One of the most common weaknesses in the Body of Christ, is not having a working, conversive, knowledge of the Bible.
There is great protection in being full of the knowledge of God—which can only happen if we fill our minds and spirits with His Word and ask the Holy Spirit to give us understanding. That means we must read it for ourselves and not depend entirely on the interpretations of others. The Word of God encompasses every part of the Armor of God—most of which is defensive, protective. Knowing the Word and acting on it is a protection from the many snares the enemy of our souls lays for us.
So we see that contending for the faith is an urgent business and involves biblical literacy.
One thing is true of most victims; they quickly become defensive of their teacher and conversive in the false doctrine they embrace. When defending their paradigm or leader, they memorize talking points, mantras, and slogans that discourage productive discussion.
Believers who depend on daily Bible devotions and Bible studies for all their Bible knowledge can still be biblically illiterate.
Daily devotions can be helpful but are limited. When these are the sum of our Bible reading, the vast majority of the Bible never gets read. The only way to ensure the protection of biblical literacy is to read our entire Bibles on a daily and systematic basis. This writer, recommends reading our Bibles every day, always picking up today where we left off yesterday.