The words pokey, poky sound the same but have different meanings and spellings. Why do pokey, poky sound the same even though they are completely different words?
The answer is simple: pokey, poky are homophones of the English language.
Slang A jail or prison.
Informal Variant of poky1.
Informal Dawdling; slow: waited for the poky sales clerk to ring up the sale.
Informal Frumpish; shabby: found poky old clothes at the thrift store.
Informal Small and cramped: a poky but inexpensive apartment.
Slang Variant of pokey1.
Definitions 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").