What is the difference between malapropism, a pun, and paronomasia?
This is the substitution of a word that sounds close to the one you'd expect, but generally has no connection to it for the purpose of humour, or to convey confusion and anxiety. For example, I can say:
After the shark attack, the swimmer was taken to hospital where he was treated and disgorged (vs. discharged).
Puns are also what are called "double-meanings" and they can take all sorts of different forms. One of my favourite novelty songs is filled with puns (I'll refrain from linking into it here as it is at least PG rated...). The song opens:
I was driving in downtown Atlantis
My Barracuda was in the shop
So I was in a rented Stingray
And it was overheating
And it goes on and on with more and more fish puns and references.
An alternate word for pun.