Unless we define what a prophet is, we will be talking French to Spanish and never get anywhere. Ok I'll start: 
(1)
General Idea -- The Hebrew Prophet was not merely, as the word commonly implies, a man enlightened by
God to foretell events; he was the interpreter and supernaturally enlightened herald sent by Yahweh to communicate His will and designs to
Israel. His mission consisted in preaching as well as in foretelling. He had to maintain and develop the knowledge of the Old Law among the
Chosen People, lead them back when they strayed, and gradually prepare the way for the new
kingdom of God, which the messias was to establish on earth. Prophecy, in general, signifies the supernatural message of the Prophet, and more especially, from custom, the predictive element of the prophetic message.
(2)
The Hebrew Names -- The ordinary Hebrew word for prophet is
nabî'. Its etymology is uncertain. According to many recent critics, the root
nabî, not employed in Hebrew, signified to speak enthusiastically, " to utter cries, and make more or less wild gestures", like the pagan mantics. Judging from a comparative examination of the cognate words in Hebrew and the other Semitic tongues, it is at least equally probable that the original meaning was merely: to speak, to utter words (cf. Laur, "Die Prophetennamen des A.T.", Fribourg, 1903, 14-38). The historic meaning of
nabî' established by biblical usage is "interpreter and mouthpiece of
God". This is forcibly illustrated by the passage, where Moses, excusing himself from speaking to Pharao on account of his embarrassment of speech, was answered by Yahweh: "Behold I have appointed thee the
God of Pharao: and Aaron thy brother shall be thy prophet. Thou shalt speak to him all that I command thee; and he shall speak to Pharao, that he let the
children of Israel go out of his land" (
Exodus 7:1-2). Moses plays towards the King of Egypt the role of
God, inspiring what is to be uttered, and Aaron is the prophet, his mouthpiece, transmitting the inspired message he shall receive. The Greek
prophetes (from
pro-phanai, to speak for, or in the name of someone) translates the Hebrew word accurately. The Greek prophet was the revealer of the future, and the interpreter of divine things, especially of the obscure oracles of the pythoness. Poets were the prophets of the muses: Inspire me, muse, thy prophet I shall be" (Pindar, Bergk, Fragm. 127).
The word
nabî' expresses more especially a function. The two most usual synonyms
ro'éeh and
hozéh emphasize more clearly the special source of the prophetic knowledge, the vision, that is, the Divine revelation or inspiration. Both have almost the same meaning;
hozéh is employed, however, much more frequently in poetical language and almost always in connexion with a supernatural vision, whereas
râ'ah, of which
ro'éh is the participle, is the usual word for to see in any manner. The compiler of the first book of Kings (ix, 9) informs us that before his time
ro'éh was used where
nabî' was then employed.
Hozéh is found much more frequently from the days of Amos. There were other less specific or more unusual terms employed, the meaning of which is clear, such as, messenger of
God, man of
God, servant of
God, man of the spirit, or inspired man, etc. It is only rarely, and at a later period, that prophecy is called
nebû'ah, a cognate of
nabî'; more ordinarily we find
hazôn, vision, or word of
God, oracle (
ne um) of Yahweh, etc.
http://www.newadvent.org/cathen/12477a.htm
