6 letter words:
fibber13,
5 letter words:
brief10,
fiber10,
fibre10,
bribe9,
4 letter words:
frib9,
fier7,
fire7,
reif7,
rife7,
bier6,
brei6,
brie6,
3 letter words:
fib8,
bib7,
ebb7,
erf6,
fer6,
fie6,
fir6,
ref6,
rif6,
reb5,
rib5,
ire3,
rei3,
2 letter words:
ef5,
fe5,
if5,
be4,
bi4,
er2,
re2,