SENTENCE: The Mona Lisa's enigmatic smile, which might show many emotions or none, has puzzled art lovers for centuries.
SYNONYMS: cryptic, perplexing, ambiguous
ANTONYMS: clear, known, obvious
DEFINITION: beyond one's powers to know, understand, or explain; not easily understood
SENTENCE: I have to trust that astrologists know what they are talking about, because I find all of the talk about signs and moons and houses to be completely inscrutable.
SYNONYMS: mysterious, strange, heady
DEFINITION: to assist tacitly; to give in without necessarily agreeing, but without protest
SENTENCE: Sonja had no wish to go to Chucky Cheese with her little brother, but he was so annoying and insistent that eventually she had to acquiesce and take him anyway.
SYNONYMS: accept, consent, accede
ANTONYMS: fight, reject, protest
DEFINITION: unaffected simplicity; lacking worldly expertise; overly ready to believe or trust in others
SENTENCE: Carrie felt ridiculous and naive for having believed the story that Matt told her about the dog with five heads.
SYNONYMS: simple, innocent, gullible
ANTONYMS: experienced, sophisticated, wise
DEFINITION: independent; not controlled by others
SENTENCE: While the dispute in Ukraine is over some eastern parts of the country becoming part of Russia, in the Middle East, many Palestinians are fighting to have their own autonomous state not governed by Israel or any other country.
SYNONYMS: self-determining, self-ruling, sovereign
ANTONYMS: dependent, subject, suppressed
DEFINITION: completely useless; doomed to failure
SENTENCE: The United States attempts to reserve sending troops into a divided country only for when all methods of diplomacy and discussion have proved futile.
SYNONYMS: useless, pointless, hopeless
ANTONYMS: fruitful, hopeful, productive
DEFINITION: natural to or characteristic of a specific people or place; belonging exclusively to a particular place
SENTENCE: Animals that are introduced to an area are likely to threaten the endemic species that have been living there for generations.
SYNONYMS: native, indigenous
DEFINITION: native to an area; existing naturally or having always lived in a place
SENTENCE: Seeing new plants and animals indigenous to a certain place is one of the joys of traveling
SYNONYMS: innate, natural, primitive
ANTONYMS: foreign, imported, alien
DEFINITION: characterized by being everywhere, especially at the same time; omnipresent
SENTENCE: Though smart phones are now ubiquitous, their power and capabilities would have amazed people just twenty years ago.