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"

Moby Thesaurus II by Grady Ward, 1.0:

112 Moby Thesaurus words for "pontificate":
   Apostolic See, Barnumize, See of Rome, aedileship, archbishopric,
   archiepiscopacy, archiepiscopate, aristocracy, bishopric, blow,
   bombast, chairmanship, chancellery, chancellorate, chancellorship,
   chiefery, chiefry, chieftaincy, chieftainry, chieftainship, cock,
   consulate, consulship, deanery, dictatorship, dictature,
   directorship, dogmatize, emirate, episcopacy, governorship,
   headship, hegemony, hierarchy, inflate, lay it on, leadership,
   look big, lordship, magistracy, magistrateship, magistrature,
   masterdom, mastership, mastery, mayoralty, mayorship,
   metropolitanate, metropolitanship, nobility, oracle, oraculate,
   papacy, papality, pashadom, pashalic, patriarchate, patriarchy,
   peacock, pile it on, pontificality, popedom, popehood, popeship,
   prefectship, prefecture, premiership, presidency, presidentship,
   prime-ministership, prime-ministry, princedom, princeship,
   principality, proclaim, proconsulate, proconsulship, protectorate,
   protectorship, provostry, provostship, put on, put on airs,
   put on side, rectorate, rectorship, regency, regentship, ritz it,
   ruling class, seigniory, seneschalship, seneschalsy, sheikhdom,
   sheriffalty, sheriffcy, sheriffdom, shrievalty, supervisorship,
   suzerainship, suzerainty, swagger, swank, swell, swell it,
   talk big, talk highfalutin, the Vatican, tribunate, vapor,
   vizierate, viziership