5 letter words:
flirs8,
furls8,
fusil8,
4 letter words:
fils7,
firs7,
flir7,
flus7,
fris7,
furl7,
furs7,
rifs7,
surf7,
lurs4,
slur4,
3 letter words:
fil6,
fir6,
flu6,
fur6,
ifs6,
rif6,
sif6,
lis3,
lur3,
sir3,
sri3,
sui3,
sur3,
2 letter words:
if5,
is2,
li2,
si2,
ur2,
us2,