6 letter words:
booker12,
rebook12,
5 letter words:
berko11,
broke11,
brook11,
ebook11,
4 letter words:
berk10,
boke10,
boko10,
book10,
bork10,
kerb10,
kobo10,
kero8,
kore8,
koro8,
roke8,
rook8,
boor6,
bore6,
broo6,
oboe6,
robe6,
3 letter words:
bok9,
keb9,
kob9,
erk7,
kor7,
oke7,
rok7,
boo5,
bor5,
bro5,
obe5,
obo5,
orb5,
reb5,
rob5,
oor3,
ore3,
reo3,
roe3,
roo3,
2 letter words:
ko6,
be4,
bo4,
ob4,
er2,
oe2,
oo2,
or2,
re2,
