unliftable
/ˌʌnˈlɪftəbəl/Definitions
1. adjective
Too heavy to be lifted by one person, or impossible to lift; unmanageable
“The unliftable weight of the machinery made it impossible to move into the new location.”
2. noun
Something that is too heavy to be lifted
“The unliftable rocks blocked the path and prevented us from reaching the top of the hill.”