uncommon
rareish
rare
semirare
Isom
geason
rare as a four-leaf clover
unique
non-English
superrare
rare as rocking horse shit
Englishy
Alwin
impostor
slip of the tongue
Shakespeare
inexpressable
Englishism
seldomness
vaguity
limitedly
potty
Duke
strictly
one in a million
seldomly
nonvernacular
unvernacular
obscurely
Hebrew
rarer than hens' teeth
unlikelily
Globish
alexical
semioccasionally
vernaculate
rare as hen's teeth
nuance
unlexical
semioccasional
nonlexical
Melodie
antrin
peculiar
subobscure
pauciloquently
semiobscure
SAT word
non-Englishness
duckspeak