6 letter words:
infeft12,
5 letter words:
feint8,
fient8,
inept7,
nepit7,
4 letter words:
pfft12,
fief10,
fife10,
niff10,
teff10,
tiff10,
feni7,
fent7,
fine7,
neif7,
nief7,
nife7,
pein6,
peni6,
pent6,
piet6,
pine6,
pint6,
nite4,
tine4,
3 letter words:
eff9,
iff9,
eft6,
fen6,
fet6,
fie6,
fin6,
fit6,
nef6,
tef6,
nep5,
nip5,
pen5,
pet5,
pie5,
pin5,
pit5,
tip5,
net3,
nie3,
nit3,
ten3,
tie3,
tin3,
2 letter words:
ef5,
fe5,
if5,
pe4,
pi4,
en2,
et2,
in2,
it2,
ne2,
te2,
ti2,