Have you ever used the word ineffable? Have you ever heard it used? The first time I stumbled across this word was while reading a poem by the 12th century abbot and poet Bernard de Clairvaux:
O Jesus, King most wonderful!
O Conqueror renowned!
O Source of peace ineffable,
In whom all joys are found.
The word "ineffable" simply means "too great to be expressed with words." So another way of saying that third line would be, "Source of indescribable peace."
As you would expect, since this word begins with the prefix "in," there is another English word which can be obtained by removing the prefix. That word is "effable." If ineffable means "too great to be expressed with words," you would probably guess -- and correctly so -- that effable means "not too great to be expressed with words," or simply, "describable."
What makes this interesting to me is that the original word, "effable," is far less common than the derived word, "ineffable."
How often have you heard the word "effable" used? I would be very surprised if you said that you hear the word "effable" more often than you hear the word "ineffable." After all, if something is describable, is there really any point to saying that it's describable? If it's describable, you just describe it, instead of mentioning the fact that it can be described!
According to Google's Ngram Viewer, when "effable" was at its most popular, "ineffable" was still about four times as popular. This happened in the early 1700s. In modern times, both words have declined in usage, but "effable" has declined much more than "ineffable." "Ineffable" is used approximately 100 times as often as effable.
Interestingly, the spell-checker I'm using while I type this blog post recognizes the word "ineffable," but tells me that I have a typo whenever I type "effable."
And since I have just described the word "ineffable," I guess we could conclude by saying that ineffable is effable.