The words seamed, seemed sound the same but have different meanings and spellings. Why do seamed, seemed sound the same even though they are completely different words?
The answer is simple: seamed, seemed are homophones of the English language.
Simple past tense and past participle of seam.
Out of condition; not in good condition.
Simple past tense and past participle of seem.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.