Unfamiliar Words with Meanings and Sentences:
1. Ephemeral: (adjective) Lasting for a very short time.
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: The internet has become ubiquitous, connecting people across the globe.
3. Serendipitous: (adjective) Occurring or discovered by chance in a happy or beneficial way.
Sentence: Our serendipitous encounter at the cafe led to a lifelong friendship.
4. Soporific: (adjective) Tending to induce drowsiness or sleep.
Sentence: The lecturer's monotone voice was soporific, sending the students into a sleepy daze.
5. Mellifluous: (adjective) Sweet or musical; pleasing to the ear.
Sentence: The singer's mellifluous voice filled the concert hall with a captivating melody.
6. Obstreperous: (adjective) Noisy and difficult to control.
Sentence: The obstreperous children refused to settle down for story time.
7. Quixotic: (adjective) Exceedingly idealistic; unrealistic and impractical.
Sentence: His quixotic dreams of becoming a famous musician were met with skepticism from his family.
8. Convivial: (adjective) Friendly and lively; enjoying the company of others.
Sentence: The party was a convivial affair, filled with laughter and conversation.
9. Anachronism: (noun) Something belonging or appropriate to a period other than that in which it exists.
Sentence: The use of cell phones in a period drama was a jarring anachronism.
10. Ephemeral: (adjective) Lasting for a very short time.
Sentence: The beauty of the cherry blossoms was ephemeral, lasting only a few weeks before they faded away.