9 letter words:
nonrubber13,
7 letter words:
unborne9,
6 letter words:
robber10,
rubber10,
bourne8,
burner8,
reborn8,
unbone8,
unbore8,
unborn8,
unrobe8,
neuron6,
runner6,
5 letter words:
berob9,
boner7,
bonne7,
borer7,
borne7,
bourn7,
burro7,
rerun5,
ronne5,
rouen5,
4 letter words:
bubo8,
burb8,
bone6,
bore6,
born6,
boun6,
bren6,
brer6,
bunn6,
burn6,
burr6,
ebon6,
robe6,
rube6,
unbe6,
euro4,
neon4,
none4,
noun4,
nurr4,
oner4,
ourn4,
rone4,
rore4,
roue4,
ruer4,
rune4,
3 letter words:
bob7,
bub7,
ebb7,
ben5,
bon5,
bor5,
bro5,
brr5,
bru5,
bun5,
bur5,
neb5,
nob5,
nub5,
obe5,
orb5,
reb5,
rob5,
rub5,
urb5,
eon3,
ern3,
err3,
non3,
nor3,
nun3,
nur3,
one3,
ore3,
our3,
ren3,
reo3,
roe3,
rue3,
run3,
ure3,
urn3,
2 letter words:
be4,
bo4,
ob4,
en2,
er2,
ne2,
no2,
nu2,
oe2,
on2,
or2,
ou2,
re2,
un2,
ur2,