Here is a context clues worksheet on the adjective extant. I think this is a word high school seniors ought to know. It means “currently or actually existing” and it turns up, in my experience, quite often in educated discourse.
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.