The Collaborative International Dictionary of English v.0.48:

Pseudo- \Pseu"do-\ [Gr. pseydh`s lying, false, akin to psey`dein
   to belie; cf. psydro`s lying, psy`qos a lie.]
   A combining form or prefix signifying false, counterfeit,
   pretended, spurious; as, pseudo-apostle, a false apostle;
   pseudo-clergy, false or spurious clergy; pseudo-episcopacy,
   pseudo-form, pseudo-martyr, pseudo-philosopher. Also used
   adjectively.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pseudo
    adj 1: (often used in combination) not genuine but having the
           appearance of; "a pseudo esthete"; "pseudoclassic"
    n 1: a person who makes deceitful pretenses [syn: imposter,
         impostor, pretender, fake, faker, fraud, sham,
         shammer, pseudo, pseud, role player]

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "pseudo":
   affected, apocryphal, artificial, assumed, bastard, bogus,
   brummagem, colorable, colored, counterfeit, counterfeited,
   distorted, dressed up, dummy, embellished, embroidered, ersatz,
   factitious, fake, faked, false, falsified, feigned, fictitious,
   fictive, forged, garbled, hokey, illegitimate, imitation, junky,
   make-believe, man-made, mock, perverted, phony, pinchbeck,
   plagiarized, pretended, put-on, quasi, queer, self-styled, sham,
   shoddy, simulated, snide, so-called, soi-disant, spurious,
   supposititious, synthetic, tin, tinsel, titivated, twisted,
   unauthentic, ungenuine, unnatural, unreal, warped, wrong



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

pseudo
 /soo'doh/, n.

    [Usenet: truncation of ?pseudonym?]

    1. An electronic-mail or Usenet persona adopted by a human for amusement
    value or as a means of avoiding negative repercussions of one's
    net.behavior; a ?nom de Usenet?, often associated with forged postings
    designed to conceal message origins. Perhaps the best-known and funniest
    hoax of this type is B1FF. See also tentacle.

    2. Notionally, a flamage-generating AI program simulating a Usenet user.
    Many flamers have been accused of actually being such entities, despite the
    fact that no AI program of the required sophistication yet exists. However,
    in 1989 there was a famous series of forged postings that used a
    phrase-frequency-based travesty generator to simulate the styles of several
    well-known flamers; it was based on large samples of their back postings
    (compare Dissociated Press). A significant number of people were fooled
    by the forgeries, and the debate over their authenticity was settled only
    when the perpetrator came forward to publicly admit the hoax.


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

pseudo

    /soo'doh/ (Usenet) Pseudonym.

   1. An electronic-mail or Usenet persona adopted by a human
   for amusement value or as a means of avoiding negative
   repercussions of one's net.behaviour; a "nom de Usenet",
   often associated with forged postings designed to conceal
   message origins.  Perhaps the best-known and funniest hoax of
   this type is BIFF.

   2. Notionally, a flamage-generating AI program simulating
   a Usenet user.  Many flamers have been accused of actually
   being such entities, despite the fact that no AI program of
   the required sophistication yet exists.  However, in 1989
   there was a famous series of forged postings that used a
   phrase-frequency-based travesty generator to simulate the
   styles of several well-known flamers; it was based on large
   samples of their back postings (compare Dissociated Press).
   A significant number of people were fooled by the forgeries,
   and the debate over their authenticity was settled only when
   the perpetrator came forward to publicly admit the hoax.

   [Jargon File]

   (1995-03-13)