5 letter words:
bourn7,
4 letter words:
bubo8,
burb8,
born6,
boun6,
burn6,
ourn4,
3 letter words:
bob7,
bub7,
bon5,
bor5,
bro5,
bru5,
bun5,
bur5,
nob5,
nub5,
orb5,
rob5,
rub5,
urb5,
nor3,
nur3,
our3,
run3,
urn3,
2 letter words:
bo4,
ob4,
no2,
nu2,
on2,
or2,
ou2,
un2,
ur2,