The Jargon File (version 4.4.7, 29 Dec 2003):

busy-wait
 vi.

    Used of human behavior, conveys that the subject is busy waiting for
    someone or something, intends to move instantly as soon as it shows up, and
    thus cannot do anything else at the moment. ?Can't talk now, I'm
    busy-waiting till Bill gets off the phone.?

    Technically, busy-wait means to wait on an event by spinning through a
    tight or timed-delay loop that polls for the event on each pass, as opposed
    to setting up an interrupt handler and continuing execution on another part
    of the task. In applications this is a wasteful technique, and best avoided
    on timesharing systems where a busy-waiting program may hog the
    processor. However, it is often unavoidable in kernel programming. In the
    Linux world, kernel busy-waits are usually referred to as spinlocks.


The Free On-line Dictionary of Computing (30 December 2018):

busy-wait

    To wait for an event by spinning through a
   tight loop or timed-delay loop that polls for the event on
   each pass, as opposed to setting up an interrupt handler and
   continuing execution on another part of the task.  This is a
   wasteful technique, best avoided on time-sharing systems
   where a busy-waiting program may hog the processor.

   [Jargon File]

   (1999-06-10)