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

guiltware
 /gilt'weir/, n.

    1. A piece of freeware decorated with a message telling one how long and
    hard the author worked on it and intimating that one is a no-good
    freeloader if one does not immediately send the poor suffering martyr gobs
    of money.

    2. A piece of shareware that works.


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

guiltware

   /gilt'weir/ 1. A piece of freeware decorated with a message
   telling one how long and hard the author worked on it and
   intimating that one is a no-good freeloader if one does not
   immediately send the poor suffering martyr gobs of money.

   2. Shareware that works.

   [Jargon File]