Unlivable means impossible or extremely difficult to live in. An unlivable apartment might have no heat in winter, broken windows, or serious water damage. An unlivable planet like Venus has temperatures hot enough to melt lead and clouds made of sulfuric acid.

The word describes conditions so bad that normal life can't continue. A house might become temporarily unlivable after a fire or flood until repairs are made. Some people call a situation unlivable when it's unbearably stressful or difficult, like saying “My schedule this week is unlivable” when they're overwhelmed with too many commitments.

Notice that unlivable is stronger than just uncomfortable or unpleasant. A bedroom that's too hot is annoying, but it's still livable. A bedroom with no roof during a rainstorm becomes unlivable. The word marks the line between “I don't like this” and “I genuinely can't stay here.”

When people work to make housing affordable and safe, they're fighting against unlivable conditions. When scientists search for planets that might support life, they're looking for places that aren't unlivable like most of our solar system.