The words teared, tiered sound the same but have different meanings and spellings. Why do teared, tiered sound the same even though they are completely different words?
The answer is simple: teared, tiered are homophones of the English language.
Simple past tense and past participle of rear.
A rank or class.
One of a series of rows placed one above another: a stadium with four tiers of seats.
To arrange (something) into or rise in tiers: tier a wedding cake; balconies that tier upward.
One that ties: a tier of knots.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License, 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").