The words cop, kop sound the same but have different meanings and spellings. Why do cop, kop sound the same even though they are completely different words?
The answer is simple: cop, kop are homophones of the English language.
Informal A police officer.
Informal One that regulates certain behaviors or actions: "Faced with the world recession of the early 1980s, ... the World Bank ... became a stern economic taskmaster and cop” ( Richard J. Barnet).
To take unlawfully or without permission; steal. See Synonyms at steal.
To get hold of; gain or win: a show that copped four awards; copped a ticket to the game.
Hill; mountain.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from the GNU version of the Collaborative International Dictionary of English 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").