pseudonymous

from WordNet (r) 3.0 (2006)

pseudonymous
    adj 1: bearing or identified by an assumed (often pen) name;
           "the writings of Mark Twain are pseudonymous"

from The Collaborative International Dictionary of English v.0.48

Pseudonymous \Pseu*don"y*mous\, a. [Gr. ?; pseydh`s false + ?,
   ?, a name: cf. F. pseudonyme. See {Pseudo-}, and {Name}.]
   Bearing a false or fictitious name; as, a pseudonymous work.
   -- {Pseu*don"y*mous*ly}, adv. -- {Pseu*don"y*mous*ness}, n.
   [1913 Webster]