7 letter words:
bonfire12,
fibroin12,
6 letter words:
biffin14,
boffin14,
iffier12,
niffer12,
fibrin11,
bonier8,
5 letter words:
fifer11,
offer11,
brief10,
fiber10,
fibre10,
finer8,
infer8,
biner7,
boner7,
borne7,
brine7,
oribi7,
robin7,
irone5,
4 letter words:
biff12,
boff12,
fief10,
fife10,
riff10,
forb9,
fern7,
fine7,
fino7,
fire7,
firn7,
foin7,
fore7,
froe7,
info7,
neif7,
reif7,
rife7,
bier6,
bine6,
biro6,
bone6,
bore6,
born6,
bren6,
brie6,
brin6,
brio6,
ebon6,
robe6,
inro4,
iron4,
noir4,
nori4,
rein4,
3 letter words:
eff9,
iff9,
off9,
fib8,
fob8,
fen6,
fer6,
fie6,
fin6,
fir6,
foe6,
fon6,
for6,
fro6,
ref6,
rif6,
ben5,
bin5,
bio5,
bro5,
neb5,
nib5,
nob5,
obe5,
obi5,
orb5,
reb5,
rib5,
rob5,
eon3,
ern3,
ion3,
ire3,
nor3,
one3,
ore3,
rei3,
rin3,
roe3,
2 letter words:
ef5,
fe5,
if5,
of5,
be4,
bi4,
bo4,
en2,
er2,
in2,
ne2,
no2,
oe2,
oi2,
on2,
or2,
re2,