5 letter words:
foist8,
tofus8,
4 letter words:
fist7,
fits7,
fous7,
fust7,
sift7,
soft7,
tofu7,
ufos7,
oust4,
outs4,
sout4,
suit4,
tuis4,
utis4,
3 letter words:
fit6,
fou6,
ifs6,
oft6,
sif6,
ufo6,
ios3,
iso3,
its3,
ous3,
out3,
sit3,
sot3,
sou3,
sui3,
tis3,
tui3,
uts3,
2 letter words:
if5,
of5,
io2,
is2,
it2,
oi2,
os2,
ou2,
si2,
so2,
st2,
ti2,
to2,
us2,
ut2,