unbreakable

unbreakable
un‧break‧a‧ble /ʌnˈbreɪkəbəl/ adjectivenot able to be broken:
    unbreakable glass
     

THESAURUS

■ not easily broken or damaged
   ▪ strong not easily broken or damaged: The bags are made of strong black plastic. | We need a strong rope for this job.
   ▪ tough strong – used especially about something that can be used a lot without damaging it or making it weaker: a pair of tough leather boots | Kitchen floors need to be tough enough to withstand heavy use.
   ▪ heavy-duty [only before noun] extremely strong – used about materials, tools, machines etc that are made especially to be used a lot without being easily damaged: heavy-duty rubber gloves | a heavy-duty carpet for the hallway
   ▪ sturdy strong and often thick, and not likely to fall over or get broken: a fence made with sturdy wooden posts | The furniture is simple but sturdy.
   ▪ unbreakable extremely strong and impossible to break: Babies need to have unbreakable dishes and cups.
   ▪ indestructible impossible to break, damage, or destroy, and lasting forever: Gold is virtually indestructible. | The pyramids were built as indestructible tombs for the Pharaohs.
   ▪ hard-wearing British English, long-wearing American English used about materials and products that will remain in good condition for a long time even when they are used a lot: Ceramic tiles are easy to keep clean and hard-wearing. | a hard-wearing fabric
   ▪ durable especially written used about materials and products that will remain in good condition for a long time – often used on product labels: The jacket has a durable nylon lining. | Varnish is more durable than paint.
   ▪ robust especially written strongly made – used especially about the structure of something, for example a vehicle or machine: a mountain bike with a robust frame | The hardware for the computer must be robust and inexpensive.