5 letter words:
brust7,
bruts7,
burst7,
4 letter words:
brus6,
brut6,
burs6,
bust6,
buts6,
rubs6,
stub6,
tubs6,
urbs6,
rust4,
ruts4,
3 letter words:
bru5,
bur5,
bus5,
but5,
rub5,
sub5,
tub5,
urb5,
rut3,
sur3,
uts3,
2 letter words:
st2,
ur2,
us2,
ut2,