7 letter words:
reefier10,
6 letter words:
reefer9,
refire9,
eerier6,
5 letter words:
firer8,
freer8,
frere8,
frier8,
refer8,
rifer8,
eerie5,
4 letter words:
fere7,
fire7,
free7,
reef7,
reif7,
rife7,
3 letter words:
fee6,
fer6,
fie6,
fir6,
ref6,
rif6,
ere3,
err3,
ire3,
ree3,
rei3,
2 letter words:
ef5,
fe5,
if5,
er2,
re2,