6 letter words:
differ13,
riffed13,
5 letter words:
fifed12,
fifer11,
fired9,
fried9,
4 letter words:
diff11,
fief10,
fife10,
riff10,
defi8,
fire7,
reif7,
rife7,
dire5,
ired5,
ride5,
3 letter words:
eff9,
iff9,
def7,
dif7,
fed7,
fid7,
fer6,
fie6,
fir6,
ref6,
rif6,
die4,
red4,
rid4,
ire3,
rei3,
2 letter words:
ef5,
fe5,
if5,
de3,
ed3,
id3,
er2,
re2,