5 letter words:
posts7,
spots7,
stops7,
stopt7,
stots5,
4 letter words:
opts6,
post6,
pots6,
psst6,
sops6,
spot6,
stop6,
tops6,
sots4,
stot4,
toss4,
tost4,
tots4,
3 letter words:
ops5,
opt5,
pot5,
pst5,
sop5,
top5,
sos3,
sot3,
tot3,
2 letter words:
op4,
os2,
so2,
to2,