The variable *load-fasl-or-lisp-file* determines whether (load "foo") should load the binary file (foo.ofasl, foo.ufasl, foo.xfasl etc, depending on platform) or foo.lisp, when both exist. It may take the following values:
If the fasl is out-of-date, the lisp file is loaded, and a warning message is output in verbose mode.
Like :load-newer, but without the warning.
Always choose fasl files in preference to lisp files, but when verbose, warn if the lisp file is newer.
Like :load-fasl, but without the warning.
Always choose lisp files in preference to fasl.
If the fasl file is out-of-date or there is none, compile and load the new fasl.
If the fasl is out-of-date, queries whether to load it, recompile and then load it, or load the lisp file.
LispWorks User Guide and Reference Manual - 20 Sep 2017