The words gilt, guilt sound the same but have different meanings and spellings. Why do gilt, guilt sound the same even though they are completely different words?
The answer is simple: gilt, guilt are homophones of the English language.
A past tense and a past participle of gild1.
Covered with gold or gilt.
Resembling gold, as in color or luster.
A thin layer of gold or something simulating gold that is applied in gilding.
The fact of being responsible for the commission of an offense. See Synonyms at blame.
Law Culpability for a crime or lesser breach of regulations that carries a legal penalty.
Remorseful awareness of having done something wrong.
Self-reproach for supposed inadequacy or wrongdoing.
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").