Archaic KJV Word
Prophet
Modern equivalent: person who predicts the future
What Was Lost
The courtroom drama. The Hebrew prophet was God's prosecuting attorney, bringing a covenant lawsuit (Hebrew rib) against Israel for breaking their agreement with God. 'Hear, O heavens, and give ear, O earth' was courtroom language -- prophets were lawyers, not fortune-tellers.
Closest Survivor in Modern English
prophet (still used but heard as 'predictor of the future' rather than 'covenant prosecutor')
Peak Usage (1611)
KJV Deuteronomy 18:15 -- 'The Lord thy God will raise up unto thee a Prophet'; Amos 3:7 -- 'The Lord God doeth nothing, but he revealeth his secret unto his servants the prophets'
Died still used but fortune-teller-ized (~1800)
Hebrew navi ('called one/spokesperson/mouthpiece of God') reduced to 'person who predicts the future.' The prophet's primary role -- speaking God's present word to present situations -- was obscured by fascination with prediction.
What Replaced It
“fortune-teller”
Prediction-focused; a navi was God's prosecuting attorney, calling the nation back to covenant faithfulness
“predictor”
Future-focused only; prophets spent most of their time addressing present injustice and covenant unfaithfulness
“visionary”
Personal insight; a prophet spoke not their own vision but God's direct word