The Collaborative International Dictionary of English v.0.48:

Factitious \Fac*ti"tious\, a. [L. factitius, fr. facere to make.
   See Fact, and cf. Fetich.]
   Made by art, in distinction from what is produced by nature;
   artificial; sham; contrived; formed by, or adapted to, an
   artificial or conventional, in distinction from a natural,
   standard or rule; not natural; as, factitious cinnabar or
   jewels; a factitious taste. -- Fac-ti"tious*ly, adv. --
   Fac*ti"tious*ness, n.
   [1913 Webster]

         He acquires a factitious propensity, he forms an
         incorrigible habit, of desultory reading. --De Quincey.

   Syn: Unnatural.

   Usage: Factitious, Unnatural. Anything is unnatural when
          it departs in any way from its simple or normal state;
          it is factitious when it is wrought out or wrought up
          by labor and effort, as, a factitious excitement. An
          unnatural demand for any article of merchandise is one
          which exceeds the ordinary rate of consumption; a
          factitious demand is one created by active exertions
          for the purpose. An unnatural alarm is one greater
          than the occasion requires; a factitious alarm is one
          wrought up with care and effort.
          [1913 Webster]

WordNet (r) 3.0 (2006):

factitious
    adj 1: not produced by natural forces; "brokers created a
           factitious demand for stocks"

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "factitious":
   affected, artificial, assumed, bogus, counterfeit, counterfeited,
   engineered, fabricated, faked, false, falsified, feigned, forced,
   imitation, insincere, man-made, manufactured, mock, pretended,
   rigged, set up, sham, simulated, spurious, synthetic, unauthentic,
   unreal