6 letter words:
bursts8,
5 letter words:
bruts7,
burst7,
busts7,
stubs7,
rusts5,
truss5,
4 letter words:
brut6,
burs6,
buss6,
bust6,
buts6,
rubs6,
stub6,
subs6,
tubs6,
urbs6,
rust4,
ruts4,
3 letter words:
bur5,
bus5,
but5,
rub5,
sub5,
tub5,
urb5,
rut3,
uts3,
2 letter words:
us2,
ut2,