The words feat, feet sound the same but have different meanings and spellings. Why do feat, feet sound the same even though they are completely different words?
The answer is simple: feat, feet are homophones of the English language.
A notable act or deed, especially an act of courage; an exploit.
An act of skill, endurance, imagination, or strength; an achievement.
Obsolete A specialized skill; a knack.
Archaic Adroit; dexterous.
Plural of foot.
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").