5 letter words:
kefir12,
fifer11,
4 letter words:
kiff14,
fike11,
firk11,
kerf11,
kief11,
fief10,
fife10,
riff10,
keir8,
kier8,
reik8,
fier7,
fire7,
reif7,
rife7,
3 letter words:
kef10,
kif10,
eff9,
iff9,
eik7,
erk7,
irk7,
kir7,
erf6,
fer6,
fie6,
fir6,
ref6,
rif6,
ire3,
rei3,
2 letter words:
ki6,
ef5,
fe5,
if5,
er2,
re2,