5 letter words:
biffs13,
fiefs11,
fifes11,
beefs10,
feebs10,
4 letter words:
biff12,
effs10,
fief10,
fife10,
beef9,
feeb9,
fibs9,
fees7,
seif7,
bees6,
bise6,
3 letter words:
eff9,
iff9,
fib8,
efs6,
fee6,
fes6,
fie6,
ifs6,
bee5,
bes5,
bis5,
sib5,
see3,
sei3,
2 letter words:
ef5,
fe5,
if5,
be4,
bi4,
es2,
is2,
si2,