6 letter words:
progun9,
5 letter words:
group8,
prong8,
4 letter words:
gorp7,
pong7,
prog7,
pung7,
porn6,
pour6,
roup6,
upon6,
rung5,
3 letter words:
pug6,
pro5,
pun5,
pur5,
upo5,
urp5,
gnu4,
gor4,
gun4,
nog4,
rug4,
nor3,
our3,
run3,
urn3,
2 letter words:
op4,
up4,
go3,
no2,
nu2,
on2,
or2,
un2,