Kenneth: While there are many verbs that are geminate in the dictionaries in order to make up triliteral roots, אפף is not one of them. Rather it is a true ayen doubled verb that is used only five times in Tanakh. In those five times it has the meaning of “to beset, hem in” as in the attacks from an enemy, and is found in 2 Samuel 22:5, Jonah 2:6, Psalms 18:5, 40:13, 116:3.Kenneth Greifer wrote:The geminate verb spelled alef pay pay might be alef pay in this quote.
Kenneth Greifer
As for אף in the phrase אף כי appears to be a word with no known verbal root.
And the word אפים in the phrase אפים כי seems to be connected with the noun אף, used in a way not too far removed from “on the face of” in English.
Isn’t linguistics fun?
Karl W. Randolph.