un·able 
/ˌʌnˈeɪbəl/ adjective
not used before a noun /ˌʌnˈeɪbəl/ adjective : not able to do something
▪ I was unable to afford the trip. ▪ He was unable to play tennis after the injury.
▪ I was unable to afford the trip. ▪ He was unable to play tennis after the injury.
