Antonyms for attainableness are unattainable, impossible, impracticable, unachievable, inaccessible, out of reach, and unobtainable. These words imply the opposite meaning of attainableness, which describes something that is achievable, feasible, or obtainable. Unattainable indicates a goal or object that cannot be reached, regardless of efforts or skills. On the other hand, impracticable suggests that something may be possible, but not feasible or advisable due to specific circumstances. Unachievable points to a goal that is beyond one's capacity, while inaccessible and out of reach describe something that is physically or mentally unreachable. Unobtainable refers to something that cannot be acquired or obtained.