8 letter words:
infinite11,
7 letter words:
finnier10,
niftier10,
tinnier7,
6 letter words:
finite9,
intern6,
intine6,
tinier6,
tinner6,
5 letter words:
feint8,
finer8,
infer8,
refit8,
inert5,
inner5,
inter5,
niter5,
nitre5,
renin5,
trine5,
4 letter words:
fern7,
fine7,
fire7,
firn7,
fret7,
frit7,
neif7,
reft7,
reif7,
rife7,
rift7,
tref7,
inti4,
nine4,
nite4,
rein4,
rent4,
rite4,
tern4,
tier4,
tine4,
tire4,
3 letter words:
eft6,
fen6,
fer6,
fet6,
fie6,
fin6,
fir6,
fit6,
ref6,
rif6,
ern3,
inn3,
ire3,
net3,
nit3,
rei3,
ret3,
rin3,
ten3,
tie3,
tin3,
2 letter words:
ef5,
fe5,
if5,
en2,
er2,
et2,
in2,
it2,
ne2,
re2,
ti2,