inutile
adjective
in·utile (ˌ)in-ˈyü-tᵊl 
-ˌtī(-ə)l
: useless, unusable
inutility
ˌin-yü-ˈti-lə-tē
noun 
Word History
Etymology
Middle English, from Anglo-French, from Latin inutilis, from in- + utilis useful — more at utility
First Known Use
15th century, in the meaning defined above