10 Unfamiliar Words and Their Synonyms in Sentences:
1. Ephemeral: (adj.) lasting for a very short time
* Sentence: The beauty of the cherry blossoms was ephemeral, fading quickly as the petals fell.
2. Ubiquitous: (adj.) present, appearing, or found everywhere
* Sentence: Smartphones are ubiquitous, found in the hands of almost everyone.
3. Gregarious: (adj.) fond of company; sociable
* Sentence: My gregarious aunt loves to host parties and gather people together.
4. Acrimonious: (adj.) bitter and angry
* Sentence: The divorce proceedings were acrimonious, filled with accusations and harsh words.
5. Mellifluous: (adj.) sweet or musical; pleasing to the ear
* Sentence: The singer's mellifluous voice filled the concert hall with warmth and emotion.
6. Quixotic: (adj.) idealistic and unrealistic
* Sentence: His quixotic dream of world peace was admirable, but ultimately impractical.
7. Inscrutable: (adj.) impossible to understand or interpret
* Sentence: The Mona Lisa's smile is inscrutable, leaving viewers pondering its meaning for centuries.
8. Serendipitous: (adj.) occurring or discovered by chance in a happy or beneficial way
* Sentence: Finding a rare book at a flea market was a serendipitous discovery.
9. Erudite: (adj.) having or showing great knowledge or learning
* Sentence: The professor's erudite lecture on ancient civilizations captivated the students.
10. Capricious: (adj.) given to sudden and unaccountable changes of mood or behavior
* Sentence: The weather was capricious, shifting from sunny to stormy in a matter of minutes.