9 letter words:
rainproof14,
8 letter words:
airproof13,
7 letter words:
pronaoi9,
orarion7,
6 letter words:
fripon11,
porina8,
5 letter words:
proof10,
friar8,
frorn8,
infra8,
apron7,
napoo7,
orpin7,
piano7,
poori7,
porno7,
prion7,
prior7,
proin7,
noria5,
4 letter words:
frap9,
poof9,
prof9,
afro7,
fain7,
fair7,
fano7,
faro7,
fiar7,
fino7,
firn7,
foin7,
fora7,
info7,
naif7,
roof7,
nipa6,
noop6,
pain6,
pair6,
parr6,
pian6,
pina6,
pion6,
pirn6,
poon6,
poor6,
porn6,
prao6,
proa6,
proo6,
roop6,
airn4,
inro4,
iron4,
naoi4,
noir4,
nori4,
orra4,
rain4,
rani4,
roan4,
roar4,
roin4,
roon4,
3 letter words:
fap8,
fop8,
arf6,
fan6,
far6,
fin6,
fir6,
fon6,
for6,
fra6,
fro6,
oaf6,
oof6,
orf6,
rif6,
apo5,
nap5,
nip5,
oop5,
pan5,
par5,
pia5,
pin5,
pir5,
poa5,
poi5,
poo5,
pro5,
rap5,
rip5,
ain3,
air3,
ani3,
ion3,
noo3,
nor3,
oar3,
ono3,
oon3,
oor3,
ora3,
rai3,
ran3,
ria3,
rin3,
roo3,
2 letter words:
fa5,
if5,
of5,
op4,
pa4,
pi4,
po4,
ai2,
an2,
ar2,
in2,
io2,
na2,
no2,
oi2,
on2,
oo2,
or2,