9 letter words:
proponent13,
8 letter words:
opponent12,
7 letter words:
propone11,
prenoon9,
6 letter words:
topper10,
operon8,
ponent8,
ponton8,
pronto8,
proton8,
enroot6,
tonner6,
5 letter words:
preop9,
netop7,
porno7,
prone7,
repot7,
toper7,
troop7,
trope7,
nonet5,
noter5,
tenon5,
tenor5,
toner5,
tonne5,
trone5,
4 letter words:
pepo8,
perp8,
poop8,
pope8,
prep8,
prop8,
repp8,
nope6,
open6,
pent6,
peon6,
pert6,
poet6,
pone6,
poon6,
poor6,
pore6,
porn6,
port6,
repo6,
rope6,
tope6,
topo6,
trop6,
neon4,
none4,
noon4,
note4,
onto4,
rent4,
root4,
rote4,
roto4,
tern4,
tone4,
toon4,
tore4,
torn4,
toro4,
3 letter words:
pep7,
pop7,
ope5,
opt5,
pen5,
per5,
pet5,
poo5,
pot5,
pro5,
rep5,
top5,
eon3,
ern3,
net3,
noo3,
nor3,
not3,
one3,
ono3,
oot3,
ore3,
ort3,
ret3,
roe3,
rot3,
ten3,
toe3,
ton3,
too3,
tor3,
2 letter words:
op4,
pe4,
en2,
er2,
et2,
ne2,
no2,
oe2,
on2,
or2,
re2,
to2,