make-timer creates and returns an unnamed timer. The function argument is a function to be applied to the remaining arguments when the timer expires. Use the function schedule-timer or schedule-timer-relative to set an expiration time.
If function returns the keyword
:stop, then timer is unscheduled (as if by unschedule-timer). This allows you to schedule a repeating timer (by passing repeat-time to schedule-timer, schedule-timer-relative, schedule-timer-milliseconds or schedule-timer-relative-milliseconds) that unschedules itself when some condition is true. Otherwise the values returned by function are ignored.
Note that the function make-named-timer creates a named timer.
LispWorks User Guide and Reference Manual - 20 Sep 2017