5 letter words:
books11,
kobos11,
4 letter words:
bisk10,
book10,
bosk10,
kobo10,
kobs10,
kois8,
sook8,
bios6,
boos6,
obis6,
3 letter words:
kob9,
kis7,
koi7,
kos7,
ski7,
bio5,
bis5,
boo5,
bos5,
obi5,
sib5,
sob5,
2 letter words:
ki6,
bi4,
bo4,
is2,
oi2,
os2,
si2,
so2,