12 letter words:
inefficiency25,
10 letter words:
efficiency23,
6 letter words:
fennec11,
5 letter words:
cynic12,
fenny11,
finny11,
fence10,
ficin10,
yince10,
niece7,
4 letter words:
iffy13,
fyce12,
fief10,
fife10,
fice9,
eyen7,
eyne7,
fine7,
neif7,
cine6,
nice6,
nene4,
nine4,
3 letter words:
eff9,
fey9,
iff9,
icy8,
eye6,
fee6,
fen6,
fie6,
fin6,
yen6,
yin6,
cee5,
ice5,
inn3,
nee3,
2 letter words:
ef5,
fe5,
if5,
ye5,
en2,
in2,
ne2,