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

malware
 n.

    [Common] Malicious software. Software intended to cause consequences the
    unwitting user would not choose; especially used of virus or Trojan
    horse software.


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

malware

    Any software designed to do something that the
   user would not wish it to do, hasn't asked it to do, and often
   has no knowledge of until it's too late.  Types of malware
   include backdoor, virus, worm, Trojan horse.

   Malware typically affects the system on which it is run,
   e.g. by deleting or corrupting files on the local disks.
   Since Internet connections became common, malware has
   increasingly targeted remote systems.  An early example was
   malware consisting of a malicious e-mail attachment that
   targeted security flaws in Microsoft Outlook (the most
   common e-mail client) to send itself to all the user's
   contacts.  A more recent kind of malware "recruits" the
   infected computer to become part of a botnet consisting of
   thousands of infected computers that can then be remotely
   controlled and used to launch DDoS attacks.

   (2007-11-15)