7 letter words:
tubifex19,
5 letter words:
befit10,
4 letter words:
fixt14,
ibex13,
exit11,
bite6,
bute6,
tube6,
etui4,
3 letter words:
fix13,
tux10,
fib8,
fub8,
eft6,
fet6,
feu6,
fie6,
fit6,
bet5,
bit5,
but5,
tub5,
tie3,
tui3,
ute3,
2 letter words:
ex9,
xi9,
xu9,
ef5,
fe5,
if5,
be4,
bi4,
et2,
it2,
ti2,
ut2,