From Latin perītus (“skillful”).

peritus (plural periti)

1. (Christianity) A Roman Catholic theologian attending an ecumenical council to give advice.
   • 2013 February 12, Tracey Rowland, “Pope Benedict XVI: God's Rottweiler or the Church's German shepherd?”, in Australian Broadcasting Corporation‎^[1]:

     Among the leading periti at Vatican II, there was an almost universal belief that this theological diet was inadequate for dealing with the problems of the late-twentieth century.

Perfect active participle of the unattested verb *perior, a root found in experior (“try, test, experience”). Cognate with Ancient Greek περᾰ́ω (perắō, “to pass through”). Compare perīculum.

• (Classical Latin) IPA^(key): [pɛˈriː.tʊs]
• (modern Italianate Ecclesiastical) IPA^(key): [peˈriː.tus]

perītus (feminine perīta, neuter perītum, comparative perītior, superlative perītissimus, adverb perītē); first/second-declension adjective

1. skillful, skilled, expert, experienced, practised (+ genitive or in + ablative or ad + accusative)

   Synonyms: expertus, gnarus, doctus, callidus, instructus, cōnsultus, sollers

   Antonyms: imperītus, rudis, inexpertus, iners, ignārus, hospes

2. clever, skilfully constructed

First/second-declension adjective.

• imperītus
• perītē
• perītia

• → Asturian: péritu
• → Catalan: perit, pèrit
• → English: perite
• → Spanish: perito
• → Galician: perito
• → Italian: perito
• Piedmontese: perì
• → Portuguese: perito
• Sicilian: piritu

• “peritus”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• “peritus”, in Charlton T. Lewis (1891), An Elementary Latin Dictionary, New York: Harper & Brothers
• "peritus", in Charles du Fresne du Cange, Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• “peritus”, in Gaffiot, Félix (1934), Dictionnaire illustré latin-français, Hachette.
• Carl Meißner; Henry William Auden (1894), Latin Phrase-Book‎^[2], London: Macmillan and Co.
  • an accomplished dialectician: disserendi peritus et artifex
    
  • a connoisseur; a specialist: (artis, artium) intellegens, peritus (opp. idiota, a layman)
    
  • statesmen: viri rerum civilium, rei publicae gerendae periti or viri in re publica prudentes
    
• Dizionario Latino, Olivetti