Which one do you mean?

About these comparisons

How were these pairs chosen?

All three kinds are computed from the corpus, not typed by hand. Homophones come from matching full phonetic transcriptions. Near-spellings come from a single-character edit at least three letters into words of six letters or more. Synonym pairs come from WordNet recording both words in the same sense while a frequency corpus puts them in different commonness bands.

Can I compare any two words?

Yes. The comparison page accepts any two entries in the dictionary — put them in the URL as word-one-vs-word-two. Only the computed pairs are listed here and offered to search engines, but the page works for anything in the corpus.

Why are some obvious pairs missing?

A pair only appears if both words clear a commonness threshold and both are in the pronouncing dictionary where the comparison needs pronunciation. Pairs involving a word too rare to be confused with anything are left out deliberately.