The Collaborative International Dictionary of English v.0.48:

Paranoiac \Par`a*noi"ac\ (p[a^]r`[.a]*noi"[a^]k), a. (Med.)
   Of or pertaining to paranoia; affected with, or
   characteristic of, paranoia; paranoid.
   [Webster 1913 Suppl. +PJC]

The Collaborative International Dictionary of English v.0.48:

Paranoiac \Par`a*noi"ac\, n.
   A person affected with paranoia.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

paranoiac
    n 1: a person afflicted with paranoia [syn: paranoid,
         paranoiac]