The words jinks, jinx sound the same but have different meanings and spellings. Why do jinks, jinx sound the same even though they are completely different words?
The answer is simple: jinks, jinx are homophones of the English language.
Plural form of jink.
Third-person singular simple present indicative form of jink.
A person or thing that is believed to bring bad luck.
A condition or period of bad luck that appears to have been caused by a specific person or thing.
To bring bad luck to.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License, from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").