Backwards when rot13'd:
an <-> na
fans <-> snaf
fobs <-> sbof
gnat <-> tang
ravine <-> enivar
re <-> er
robe <-> ebor
serf <-> fres
tang <-> gnat
thug <-> guht
uh <-> hu

Other word when rot13'd:
ah <-> nu
aha <-> nun
ant <-> nag
balk <-> onyx
bar <-> one
barf <-> ones
be <-> or
bin <-> ova
crag <-> pent
ebbs <-> roof
envy <-> rail
errs <-> reef
flap <-> sync
fur <-> she
gel <-> try
gnat <-> tang
if <-> vs
irk <-> vex