The words slew, slough, slue sound the same but have different meanings and spellings. Why do slew, slough, slue sound the same even though they are completely different words?
The answer is simple: slew, slough, slue are homophones of the English language.
Informal A large amount or number; a lot: a slew of unpaid bills.
Past tense of slay.
Variant of slough1.
Variant of slue1.
A depression or hollow, usually filled with deep mud or mire.
A stagnant swamp, marsh, bog, or pond, especially as part of a bayou, inlet, or backwater.
A state of deep despair or moral degradation.
The dead outer skin shed by a reptile or amphibian.
To turn (something) on an axis; rotate: slued the swivel chair around; sluing the boom of a crane.
To turn sharply; veer: braked and slued the car around.
To turn about an axis; pivot.
To turn or slide sideways or off course; skid.
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").