In Modern Hebrew, a praklit פרקליט is an attorney - and the State Attorney's office is known as פרקליטות המדינה - Praklitut HaMedina.
However, in the Mishna, where it first appears, praklit means "advocate, intercessor", as in Avot 4:13 - העושה מצוה אחת, קנה לו פרקליט אחד - "Whoever does one mitzva, acquires a praklit for himself" and Sifra Metzora 3:3 - חטאת דומה לפרקליט שנכנס לרצות - "A sin offering is like a praklit that enters the (royal palace) to appease (the king)." It is also the translation by the Targum for the Hebrew melitz מליץ in Iyov 16:20.
The word derives from Greek, and Klein provides the following etymology:
Greek parakletos (= advocate), verbal adjective of parakatein (= to call to aid, summon, invite, console, exhort, encourage), from para ( = beside), and kalein ( = to call), which is cognate with Latin calare ( = to proclaim, call, shout).
Joel Hoffman in his book In the Beginning: A Short History of the Hebrew Language points out that Klein's entry has a typographical error, and writes that "the Greek verb "to call" from which the word ultimately derives is parakalein, not parakatein."
The word made its way into English as well as paraclete - meaning "comforter", and is found in Christian and Moslem tradition.