fact of life
unavoidable
unpreventable
spilt milk
bound to
impossible
cannot
inseparable
forbidden fruit
no go
immutable
unchangeable
unbreakable
unmitigably
nonnegotiable
unextinguishably
nonessential
shouldn't
indispensable
inessential
nonbreakable
unspoilably
ineliminably
unappeasably
avoidable
undoable
genie is out of the bottle
incapacitate
inevitably
shunless
you can't unring a bell
mandatorily
compulsorily
obligatorily
nonthreat
restrainer
nonemergency
feculence
unquenchably
preventable
unresistable
keepable
unneglectable
unobservable
uninhibitable
unknowable
unattainable
unessentials
unhidable
possible
unerasable
unerasably
unnecessity
inconsequentiality
imperfectibly
insuppressible
impossibility
sweep under the rug
impracticality
possibilium
unbesmirchable
illutible
unsubduable
unchewable
unpindownable
nonstandard
lamesauce
do
nonessentiality
desirement
indispensably
inevitable
non-prerequisite
can't be fucked
need-not
unassailable
unsubduably
nonavoidable
inconfinable
unaskable
guard against
poison
unconfinable
unoppressively
ticket to ride
undrainable
unslakable
antidote
undetachably
unsilenceably
inexhaustible
misappearance
unlimited
time-waster
noncomestible
nonexample
get out of jail free card