6 letter words:
niffer12,
ferine9,
refine9,
repine8,
5 letter words:
fifer11,
finer8,
infer8,
preen7,
repin7,
ripen7,
4 letter words:
fief10,
fife10,
riff10,
fere7,
fern7,
fine7,
fire7,
firn7,
free7,
neif7,
reef7,
reif7,
rife7,
neep6,
peen6,
peer6,
pein6,
pere6,
peri6,
pier6,
pine6,
pirn6,
pree6,
ripe6,
erne4,
rein4,
3 letter words:
eff9,
iff9,
fee6,
fen6,
fer6,
fie6,
fin6,
fir6,
ref6,
rif6,
nip5,
pee5,
pen5,
per5,
pie5,
pin5,
rep5,
rip5,
ere3,
ern3,
ire3,
nee3,
ree3,
rei3,
rin3,
2 letter words:
ef5,
fe5,
if5,
pe4,
pi4,
en2,
er2,
in2,
ne2,
re2,