Archaic KJV Word
Convenient
Modern equivalent: fitting
What Was Lost
The moral architecture of the word. When Paul said certain behaviors were 'not convenient,' he did not mean they were inconvenient or hard to schedule. He meant they did not fit -- they were morally incoherent, actions that violated the created order. Convenience was a moral category before it became a consumer preference.
Closest Survivor in Modern English
convene (to come together -- preserves the Latin root of 'fitting together')
Peak Usage (1611)
KJV Romans 1:28 -- 'To do those things which are not convenient'; Ephesians 5:4 -- 'Jesting, which are not convenient'
Died ~1800
Weakened from 'morally fitting/proper/suitable by divine standard' (Latin convenire 'to come together/agree') to 'easy/requiring little effort,' evacuating all moral content.
What Replaced It
“fitting”
Closer to the original but lacks moral weight; convenient-as-fitting meant aligned with God's created order
“proper”
Social convention; convenient meant cosmically proper -- aligned with how things ought to be
“appropriate”
Contextual and relative; convenient carried absolute moral judgment