unsinkable

/ʌnˈsɪŋkəbəl/
adjective
  1. Unable to sink; designed or made so that it cannot go under water.
    • They claimed the new ship was unsinkable, but it hit an iceberg.
    • The lifeboat was made of unsinkable materials.
    • Modern kayaks are often unsinkable because of built-in flotation chambers.
  2. Figuratively, impossible to defeat, destroy, or discourage; very resilient.
    • Her unsinkable optimism kept the team going through the crisis.
    • He has an unsinkable spirit that never gives up.
    • The company seemed unsinkable, surviving every economic downturn.
Antonyms
What does "unsinkable" mean? | whatsthatwordmean | whatsthatwordmean