Meaning ofunthinkablein English

Adjective

1. goes against common sense; unimaginable
   It's unthinkable that she would leave her job without a plan.
2. defies belief; highly improbable
   The idea of traveling to Mars in the near future seems unthinkable to many people.
3. violates social norms; extremely improper
   It is unthinkable for a guest to arrive empty-handed at a dinner party.