The Collaborative International Dictionary of English v.0.48:

Pontificate \Pon*tif"i*cate\, v. i. (R. C. Ch.)
   To perform the duty of a pontiff.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pontificate \Pon*tif"i*cate\, n. [L. pontificatus: cf. F.
   pontificat. See Pontiff.]
   1. The state or dignity of a high priest; specifically, the
      office of the pope. --Addison.
      [1913 Webster]

   2. The term of office of a pontiff. --Milman.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pontificate
    n 1: the government of the Roman Catholic Church [syn: papacy,
         pontificate]
    v 1: administer a pontifical office
    2: talk in a dogmatic and pompous manner; "The new professor
       always pontificates"