I am looking for a word that describes the mistaking of a word for one that sounds similar. For instance "you aren't allowed to do that, but I guess we can make a deception." Obviously, "deception" should be "exception." The words don't sound the same, but they're pretty close.
The mistaken use of a word in place of a similar-sounding one, often with unintentionally amusing effect, as in, for example, “dance a flamingo” (instead of flamenco).
a word or phrase that results from a mishearing or misinterpretation of another, an element of the original being substituted for one that sounds very similar or identical (e.g. tow the line instead of toe the line ).
How about "catachresis?"
catachresis: the incorrect use of words, as luxuriant for luxurious.
A special class of this situation is a mondegreen:
the mishearing or misinterpretation of a phrase as a result of near-homophony, in a way that gives it a new meaning.