CL-USER> (unintern :test (find-package :keyword))
T

CL-USER> (find 3 '(1 2 3 4 5) :test #'=)

debugger invoked on a UNKNOWN-KEYWORD-ARGUMENT in thread
#<THREAD "main thread" RUNNING {1000508083}>:
  Unknown &KEY argument: :TEST

Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [CONTINUE] Ignore all unknown keywords
  1: [ABORT   ] Exit debugger, returning to top level.

(FIND 3 (1 2 3 4 5) :TEST #<FUNCTION =>) [more]