5 letter words:
biffo13,
boffo13,
oobit7,
4 letter words:
biff12,
boff12,
tiff10,
toff10,
foot7,
bito6,
boot6,
obit6,
3 letter words:
iff9,
off9,
fib8,
fob8,
fit6,
oft6,
oof6,
bio5,
bit5,
boi5,
boo5,
bot5,
obi5,
obo5,
oot3,
too3,
2 letter words:
if5,
of5,
bi4,
bo4,
ob4,
io2,
it2,
oi2,
oo2,
ti2,
to2,