9 letter words:
turboprop15,
7 letter words:
purport11,
6 letter words:
torpor8,
uproot8,
5 letter words:
burro7,
robot7,
troop7,
turbo7,
rotor5,
4 letter words:
burp8,
poop8,
prop8,
boor6,
boot6,
bort6,
bout6,
broo6,
brut6,
burr6,
poor6,
port6,
pour6,
pout6,
purr6,
roup6,
topo6,
trop6,
root4,
roto4,
rout4,
toro4,
torr4,
tour4,
3 letter words:
bop7,
pop7,
pub7,
pup7,
boo5,
bot5,
bro5,
brr5,
bur5,
but5,
opt5,
orb5,
poo5,
pot5,
pro5,
pur5,
put5,
rob5,
rub5,
top5,
tub5,
tup5,
upo5,
urb5,
urp5,
oot3,
ort3,
our3,
out3,
rot3,
rut3,
too3,
tor3,
2 letter words:
bo4,
op4,
up4,
or2,
to2,
ut2,
