a. [ L. suppositicus. See Supposition. ] 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. [ 1913 Webster ]

2. Suppositional; hypothetical. [ R. ] Woodward. [ 1913 Webster ]

-- Sup*pos`i*ti"tious*ly, adv. -- Sup*pos`i*ti"tious*ness, n. [ 1913 Webster ]