cl-nset-difference is an autoloaded compiled Lisp function in `cl-seq.el'.

(cl-nset-difference LIST1 LIST2 [KEYWORD VALUE]...)

Combine LIST1 and LIST2 using a set-difference operation.
The resulting list contains all items that appear in LIST1 but not LIST2.
This is a destructive function; it reuses the storage of LIST1 and LIST2
whenever possible.

Keywords supported: :test :test-not :key