uncrushable
adjective
un·crush·able ˌən-ˈkrə-shə-bəl 
: impossible to crush : not crushable
an uncrushable spirit
uncrushable materials
Example Sentences
Recent Examples on the Web Pack cookies in airtight, durable, uncrushable containers of the proper size, such as common food storage containers or decorative tins. 
Washington Post, 4 Dec. 2020 This speaker is protected by a pelican case that is uncrushable and can withstand extreme weather conditions. Popular Science, 7 July 2020
Washington Post, 4 Dec. 2020 This speaker is protected by a pelican case that is uncrushable and can withstand extreme weather conditions. Popular Science, 7 July 2020 Word History
First Known Use
1873, in the meaning defined above