Which of the following does not end with ff?

The correct answer is: Beech

The most frequent double letter combinations are ee, ll, ss, oo, tt, ff, rr, pp, and cc. The double letters that occur most commonly at the end of words are ee, ll, ss, and ff. There is two word 'whiff' and 'beech'. Both words have double letter (ff and ee). So, the word 'beech' does not end with 'ff'.