at latter Lammas
at no time
if pigs had wings
when pigs fly
never ever
when two Sundays meet
when two Sundays come together
not while pussy's a cat
nevah
nary
nooit
under no circumstances
in no way
in a pig's eye
never've
nevermore
Neveruary
unreddened
relentless
persistent
unrelenting
only
only when
only if
nondermal
when Hell freezes over
uneverted
nix
⠐⠑
unvenial
second Tuesday of the week
unproffered
unpealed
uneven
stop
of all time
inavertible
you'ven't
undying
last trump
nondegreased
entire
Crotophaga
deathless
genus Crotophaga
unbewailed
ungiven
don't even think about it
non-con
inexistent