5 letter words:
force10,
4 letter words:
corf9,
fere7,
fore7,
free7,
froe7,
reef7,
cere6,
cero6,
core6,
3 letter words:
fee6,
fer6,
foe6,
for6,
fro6,
ref6,
cee5,
cor5,
orc5,
rec5,
roc5,
ere3,
ore3,
ree3,
roe3,
2 letter words:
ef5,
fe5,
of5,
er2,
oe2,
or2,
re2,