Supposititious

Part of speech: adjective (a.)

1. Fraudulently substituted for something else; not being what is purports to be; not genuine; spurious; counterfeit; as, a supposititious child; a supposititious writing. Bacon.

2. Suppositional; hypothetical. [R.] Woodward. -- Sup*pos`i*ti"tious*ly, adv. -- Sup*pos`i*ti"tious*ness, n.