7 letter words:
fittest10,
5 letter words:
feist8,
4 letter words:
efts7,
fest7,
fets7,
fist7,
fits7,
seif7,
sift7,
sett4,
site4,
stet4,
test4,
tets4,
ties4,
tits4,
3 letter words:
efs6,
eft6,
fes6,
fet6,
fie6,
fit6,
ifs6,
its3,
sei3,
set3,
sit3,
tet3,
tie3,
tis3,
tit3,
2 letter words:
ef5,
fe5,
if5,
es2,
et2,
is2,
it2,
si2,
ti2,