The Collaborative International Dictionary
Pseudonymousness
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.
Wiktionary
pseudonymousness
n. The quality of being pseudonymous.