9 letter words:
fistfight19,
6 letter words:
fifths15,
fights13,
tights10,
5 letter words:
fifth14,
fight12,
shift11,
stiff11,
tiffs11,
gifts9,
sight9,
tight9,
titis5,
4 letter words:
fish10,
tiff10,
figs8,
ghis8,
gift8,
sigh8,
fist7,
fits7,
hist7,
hits7,
shit7,
sift7,
sith7,
this7,
gist5,
gits5,
titi4,
tits4,
3 letter words:
iff9,
fig7,
ghi7,
fit6,
his6,
hit6,
ifs6,
git4,
its3,
sit3,
tis3,
tit3,
2 letter words:
hi5,
if5,
sh5,
is2,
it2,
si2,
ti2,
