Two words with similar spellings but different meanings and different pronunciations. The spellings are identical except for a single double character.
Such word pairings are useful in wordplay or poetry.
Examples include:
eelfish elfish
fiancee fiance
furry fury
good god
starring staring
Overabundant use of Blake Blakkes:
After my super supper in the dinner diner I had dessert in the desert and my ass grew looser like a loser.