5 letter words:
booky14,
booby12,
yobbo12,
4 letter words:
kybo13,
boko10,
book10,
kobo10,
boyo9,
boob8,
3 letter words:
kow10,
wok10,
yok10,
bok9,
kob9,
yow9,
bow8,
boy8,
yob8,
bob7,
woo6,
boo5,
obo5,
2 letter words:
ky9,
by7,
ko6,
ow5,
oy5,
wo5,
yo5,
bo4,
ob4,
oo2,