There are a total of 49 4-letter words containing 'ff', and the number may vary in different dictionaries. You can specify the dictionary and order.

• baff ₁₃
• biff ₁₃
• boff ₁₃
• buff ₁₄
• caff ₁₃
• coff ₁₃
• cuff ₁₄
• daff ₁₁
• diff ₁₁
• doff ₁₁
• duff ₁₂
• effs ₁₀
• faff ₁₃
• gaff ₁₂
• guff ₁₃
• huff ₁₃
• iffy ₁₂
• jiff ₁₉
• luff ₁₂
• miff ₁₃
• muff ₁₄
• naff ₁₁
• niff ₁₁
• nuff ₁₂
• offs ₁₀
• offy ₁₂
• pfft ₁₃
• puff ₁₄
• raff ₁₀
• riff ₁₀
• ruff ₁₁
• teff ₁₀
• tiff ₁₀
• toff ₁₀
• tuff ₁₁
• waff ₁₃
• wuff ₁₄
• yaff ₁₂
• ziff ₁₉
• offa ₁₀
• viff ₁₃
• affy ₁₃
• fuff ₁₃
• goff ₁₁
• haff ₁₃
• jeff ₁₇
• kiff ₁₄
• koff ₁₄
• meff ₁₂

There are 49 4-letter words containing ff in the well-known word game dictionary, 38 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 45 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 39 in the Words with Friends (WWF) dictionary.