7 letter words:
infixes17,
6 letter words:
nixies13,
5 letter words:
fixes15,
infix15,
nixes12,
nixie12,
fines8,
finis8,
neifs8,
nisei5,
4 letter words:
nixe11,
fens7,
fine7,
fins7,
neif7,
seif7,
nisi4,
sine4,
3 letter words:
fix13,
nix10,
sex10,
six10,
xis10,
efs6,
fen6,
fes6,
fie6,
fin6,
ifs6,
ens3,
ins3,
sei3,
sen3,
sin3,
2 letter words:
ex9,
xi9,
ef5,
fe5,
if5,
en2,
es2,
in2,
is2,
ne2,
si2,