Archaic KJV Word
Sore
Modern equivalent: greatly
What Was Lost
The embodied intensity. Being 'sore afraid' was not just very frightened but frightened to the point of physical pain -- fear so intense your body ached. 'Sore lamentation' was grief that physically hurt. The word made emotions visceral, bodily, real. When sore became only a wound, the intensifier that made biblical emotions physical disappeared.
Closest Survivor in Modern English
sorely ('sorely missed' preserves the intensifier meaning)
Peak Usage (1611)
KJV Genesis 50:10 -- 'They mourned with a great and very sore lamentation'; Matthew 17:6 -- 'They fell on their face, and were sore afraid'
Died ~1800 (the intensifier meaning faded)
Narrowed from a powerful intensifier meaning 'greatly/severely/exceedingly' to only 'painful/wounded,' removing English's most common biblical intensifier.
What Replaced It
“greatly”
Mild; sore-as-intensifier meant overwhelmingly, almost unbearably
“very”
Weak; sore carried physical force -- it made the modified word hurt
“terribly”
Followed the same degradation path as awful and terrible