6 letter words:
fitter9,
titfer9,
titter6,
5 letter words:
fitte8,
freit8,
fritt8,
refit8,
rifte8,
treif8,
tetri5,
titer5,
titre5,
trite5,
4 letter words:
fett7,
fier7,
fire7,
fitt7,
fret7,
frit7,
reft7,
reif7,
rife7,
rift7,
terf7,
tift7,
tref7,
rite4,
ritt4,
tier4,
tire4,
tite4,
tret4,
trie4,
3 letter words:
eft6,
erf6,
fer6,
fet6,
fie6,
fir6,
fit6,
ref6,
rif6,
tef6,
ire3,
rei3,
ret3,
rit3,
tet3,
tie3,
tit3,
2 letter words:
ef5,
fe5,
if5,
er2,
et2,
it2,
re2,
te2,
ti2,