Which word ends with ff?

The correct answer is: Staff

The most frequent double letter combinations are ee, ll, ss, oo, tt, ff, rr, nn, pp, and cc. The double letters that occur most commonly at the end of words are ee, ll, ss, and ff. There is two words staff and elbow. Only the word 'staff' has double letter. So, the word ends with 'ff' is 'staff'.