camel through the eye of a needle
adynaton
rule out
impossibility
nail Jell-O to a tree
far-fetched
farfetched
aporia
bitterly
good for someone
unfeasibly
unachievability
surreality
incomprehensibility
impracticableness
impracticality
inconcludable
hyperbolism
Heath Robinsonian
indescribable
unfulfillably
indemonstrably
eggs in moonshine
impracticably
pie in the sky
unexpressibly
ab absurdo
impracticalness
impracticability
profundify
promise the moon
Barmecide feast
unserviceable
hyperbolics
profundicate
undoable
unthinkableness
incomprehensibleness
conflict
best laid plans
unthinkability
impractically
chase a rainbow
muddy the waters
absurd
absurdification
make it make sense
unlikeliness
imperfectibly
airy fairy