bitter
impossible
insufferable
unacceptable
unsufferable
unsupportable
unendurability
unendurableness
acutest
excruciating
frightful
impracticable
inconsolable
inexpressible
insurmountable
madden
overpower
pent-up
poignant
sicken
speechless
unbearable
unbelievable
unimaginable
unmerited
unmitigated
unthinkable
untold