Unfamiliar Words and Their Meanings:
1. Ephemeral: (adjective) lasting for a very short time; fleeting.
* Sentence: The beauty of the cherry blossoms was ephemeral, lasting only a few weeks before they faded away.
2. Ubiquitous: (adjective) present, appearing, or found everywhere.
* Sentence: Smartphones have become ubiquitous, with nearly everyone owning one.
3. Serendipity: (noun) the occurrence and development of events by chance in a happy or beneficial way.
* Sentence: By sheer serendipity, I found a rare first edition of my favorite book at a flea market.
4. Mellifluous: (adjective) sweet or musical; pleasing to the ear.
* Sentence: The singer's mellifluous voice captivated the audience.
5. Quixotic: (adjective) exceedingly idealistic; unrealistic and impractical.
* Sentence: His quixotic plan to single-handedly reform the entire government system was doomed to failure.
6. Soporific: (adjective) tending to induce drowsiness or sleep.
* Sentence: The professor's monotonous voice had a soporific effect on the students.
7. Petrichor: (noun) the pleasant, earthy scent after rain.
* Sentence: The first rain after a long drought brought with it the sweet smell of petrichor.
8. Schadenfreude: (noun) pleasure derived from the misfortunes of others.
* Sentence: There was a distinct air of schadenfreude among the students who had passed the exam, as those who failed were openly ridiculed.
9. Ephemeris: (noun) a table showing the calculated positions of celestial objects at a given time or times.
* Sentence: The astronomer used the ephemeris to predict the exact time of the solar eclipse.
10. Labyrinthine: (adjective) like a labyrinth; intricate and confusing.
* Sentence: The city's underground subway system was a labyrinthine network of tunnels and corridors.
11. Misanthrope: (noun) a person who dislikes humankind and avoids human society.
* Sentence: The reclusive writer was known as a misanthrope, rarely interacting with anyone.
12. Effervescent: (adjective) lively and spirited; bubbly.
* Sentence: Her effervescent personality lit up the room.
13. Anachronism: (noun) a thing belonging or appropriate to a period other than that in which it exists, especially a thing that is conspicuously old-fashioned.
* Sentence: The knight wearing chain mail in the 21st century was an anachronism.
14. Sycophant: (noun) a person who tries to win favor from wealthy or influential people by flattering them.
* Sentence: The sycophant constantly praised the CEO's every decision, hoping to get a promotion.
15. Zeitgeist: (noun) the defining spirit or mood of a particular period of history as shown by the ideas and beliefs of the time.
* Sentence: The rebellious spirit of the 1960s was a manifestation of the zeitgeist of that era.