1.Stubborn(adjective): The girl was stubborn, and he knew there was no time for argument.
Synonyms:adamant,determined
Antonyms:flexible,irresolute
Example Sentence: As he stared at the stubborn face of Burton, his eyes hardened.
2.sterile(adjective): free from living germs or microorganisms
Synonyms: antiseptic ,arid
Antonyms:cheerful,contaminated
Example Sentence:We ‘ve found the dead and sterile remains of their civilization.
3.prudent(adjective): wise or judicious in practical affairs
Synonyms: vigilant,advisable
Antonyms: careless,expensive
Example Sentence:That sacrifice may also be aprudentaction,” observed Madeleine.
4.Obstinate(adjective): Not yielding readily to treatment, as a disease.
Synonyms: adamant,dogmatic
Antonyms:amenable,flexible
Example Sentence: The struggle in Congress over the Lecompton bill was obstinate.
5.Stalwart(adjective): strongly and stoutly built; sturdy and robust.
Synonyms: dependable,fearless
Antonyms: timid,undependable
Example Sentence: They were a stalwart people, versed in agriculture and working in metal.