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

WIMP environment
 n.

    [acronym: ?Window, Icon, Menu, Pointing device (or Pull-down menu)?] A
    graphical-user-interface environment such as X or the Macintosh
    interface, esp. as described by a hacker who prefers command-line
    interfaces for their superior flexibility and extensibility. However, it is
    also used without negative connotations; one must pay attention to voice
    tone and other signals to interpret correctly. See menuitis, 
    user-obsequious.


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

WIMP
WIMP environment

    Windows, Icons, Menus and Pointers
   (or maybe Windows, Icons, Mouse, Pull-down menus).

   The style of graphical user interface invented at Xerox
   PARC, popularised by the Apple Macintosh and now available
   in other varieties such as the X Window System,
   OSF/Motif, NeWS, RISC OS and Microsoft Windows.

   See menuitis, user-obsequious, window system.

   (2007-09-12)