6 letter words:
fifers12,
5 letter words:
fiefs11,
fifer11,
fifes11,
riffs11,
fiers8,
fires8,
fries8,
frise8,
reifs8,
serif8,
4 letter words:
effs10,
fief10,
fife10,
riff10,
feis7,
fier7,
fire7,
firs7,
fris7,
refs7,
reif7,
rife7,
rifs7,
seif7,
serf7,
ires4,
reis4,
rise4,
seir4,
sire4,
3 letter words:
eff9,
iff9,
efs6,
erf6,
fer6,
fes6,
fie6,
fir6,
ifs6,
ref6,
rif6,
sif6,
ers3,
ire3,
rei3,
res3,
sei3,
ser3,
sir3,
sri3,
2 letter words:
ef5,
fe5,
if5,
er2,
es2,
is2,
re2,
si2,