The video defines active vocabulary (words you use effortlessly, e.g., 'house', 'chair') versus passive vocabulary (words you know but avoid using due to uncertainty or fear). The speaker urges learners to work on converting passive words into active use so those words become retrievable and usable in speech.
Chapters
Active vocabulary is basically the words that you constantly use without thinking about it. You retrieve them rather easily without a lot of thought. House, chair, kids. Okay, these are easy words for you to use, and you don't get self conscious about using them. But then there is the passive vocabulary. That is words that you know but you don't really use because you're afraid of using them incorrectly. Or maybe you're not sure about the pronunciation, and all of that causes you to keep them stuck back there in your subconscious, and it's only triggered when you hear those words, but you don't use them. And what a shame, because you can use them. You know those words, right? And if you feel that you're not very strong in that area, then it means that you need to work on turning those passive words, the words that you know but never use, into active words.