5 letter words:
firms10,
firns8,
minus7,
munis7,
ruins5,
4 letter words:
firm9,
fins7,
firn7,
firs7,
funs7,
furs7,
rifs7,
surf7,
mirs6,
muni6,
muns6,
nims6,
rims6,
rums6,
rins4,
ruin4,
runs4,
urns4,
3 letter words:
fin6,
fir6,
fun6,
fur6,
ifs6,
rif6,
ism5,
mir5,
mis5,
mun5,
mus5,
nim5,
rim5,
rum5,
sim5,
sum5,
ins3,
nus3,
rin3,
run3,
sin3,
sir3,
sri3,
sun3,
uns3,
urn3,
2 letter words:
if5,
mi4,
mu4,
um4,
in2,
is2,
nu2,
si2,
un2,
us2,