A function-dspec Specifies the function definition to which the piece of advice belongs. See Function dspecs for description of function-dspec.
A symbol naming the piece of advice to be removed. Since several pieces of advice may be attached to a single functional definition, the name is necessary to indicate which one is to be removed.
remove-advice is the function used to remove a piece of advice. Advice is a way of altering the behavior of functions. Pieces of advice are associated with a function using defadvice. They define additional actions to be performed when the function is invoked, or alternative code to be performed instead of the function, which may or may not access the original definition. As well as being attached to ordinary functions, advice may be attached to methods and to macros (in this case it is in fact associated with the macro's expansion function).
LispWorks User Guide and Reference Manual - 20 Sep 2017