The words bogey, bogie, bogy sound the same but have different meanings and spellings. Why do bogey, bogie, bogy sound the same even though they are completely different words?
The answer is simple: bogey, bogie, bogy are homophones of the English language.
Slang A detective or police officer.
An evil or mischievous spirit; a hobgoblin.
A cause of annoyance or harassment.
Sports The number of strokes that a good player is likely to need to finish a golf hole or course.
One of several wheels or supporting and aligning rollers inside the tread of a tractor or tank.
Chiefly British A railroad car or locomotive undercarriage having pairs of wheels that swivel so that curves can be negotiated.
Variant of bogey.
Variant of bogey.
Variant of bogie1.
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").