6 letter words:
fetter9,
fitter9,
titfer9,
5 letter words:
fiere8,
fitte8,
freet8,
freit8,
fritt8,
refit8,
rifte8,
terfe8,
treif8,
retie5,
tetri5,
titer5,
titre5,
trite5,
4 letter words:
feer7,
feet7,
fere7,
fete7,
fett7,
fier7,
fire7,
fitt7,
free7,
fret7,
frit7,
reef7,
reft7,
reif7,
rife7,
rift7,
terf7,
tift7,
tref7,
rete4,
rite4,
ritt4,
teer4,
tete4,
tier4,
tire4,
tite4,
tree4,
tret4,
trie4,
3 letter words:
eft6,
erf6,
fee6,
fer6,
fet6,
fie6,
fir6,
fit6,
ref6,
rif6,
tef6,
ere3,
ire3,
ree3,
rei3,
ret3,
rit3,
tee3,
tet3,
tie3,
tit3,
2 letter words:
ef5,
fe5,
if5,
ee2,
er2,
et2,
it2,
re2,
te2,
ti2,