7 letter words:
backups17,
6 letter words:
backup16,
5 letter words:
backs13,
bucks13,
packs13,
pucka13,
pucks13,
bauks11,
cauks11,
bapus9,
caups9,
scaup9,
scuba9,
4 letter words:
back12,
buck12,
pack12,
puck12,
bask10,
bauk10,
busk10,
cask10,
cauk10,
cusk10,
kabs10,
puka10,
sack10,
suck10,
auks8,
bacs8,
baps8,
bapu8,
cabs8,
caps8,
caup8,
cubs8,
cups8,
cusp8,
pacs8,
pubs8,
scab8,
scup8,
skua8,
suba6,
upas6,
3 letter words:
kab9,
ask7,
auk7,
bac7,
bap7,
cab7,
cap7,
cub7,
cup7,
kas7,
pac7,
pub7,
ska7,
suk7,
abs5,
asp5,
bas5,
bus5,
pas5,
pus5,
sab5,
sac5,
sap5,
spa5,
sub5,
sup5,
ups5,
sau3,
2 letter words:
ka6,
ab4,
ba4,
pa4,
up4,
as2,
us2,