5 letter words:
fixes15,
exist12,
exits12,
sixte12,
feist8,
fetes8,
4 letter words:
fixt14,
exes11,
exit11,
sext11,
efts7,
fees7,
feet7,
fest7,
fete7,
fets7,
fist7,
fits7,
seif7,
sift7,
site4,
tees4,
ties4,
3 letter words:
fix13,
sex10,
six10,
xis10,
efs6,
eft6,
fee6,
fes6,
fet6,
fie6,
fit6,
ifs6,
its3,
see3,
sei3,
set3,
sit3,
tee3,
tie3,
tis3,
2 letter words:
ex9,
xi9,
ef5,
fe5,
if5,
es2,
et2,
is2,
it2,
si2,
ti2,