9 letter words:
tiffining16,
7 letter words:
niffing14,
tiffing14,
6 letter words:
fifing13,
tiffin12,
fining10,
tining7,
4 letter words:
fifi10,
niff10,
tiff10,
gift8,
fini7,
ginn5,
ting5,
inti4,
3 letter words:
iff9,
fig7,
gif7,
fin6,
fit6,
gin4,
git4,
tig4,
inn3,
nit3,
tin3,
2 letter words:
if5,
gi3,
in2,
it2,
ti2,