Free monads in Haskell are a powerful abstraction that allows for the creation of monadic structures without imposing additional constraints beyond those required by the monad definition. They are "free" in the sense that they are unrestricted, meaning they do not add any extra laws or structure beyond what is necessary for a monad.

A free monad satisfies all the Monad laws, but does not do any computation. It just builds up a nested series of contexts. The user who creates such a free monadic value is responsible for doing something with those nested contexts, so that the meaning of such a composition can be deferred until after the monadic value has been created.