1,422 word pairs that get mixed up, in three kinds: words that sound identical, words that look almost identical, and words that mean nearly the same thing. Each comparison puts the two side by side — pronunciation, part of speech, senses, and which of the two you are more likely to meet.
Pairs WordNet records as sharing a sense, but which sit in different commonness bands. The question is not what they mean, it is which one belongs in your sentence.