from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Impossible to attain: unattainable goals.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Impossible to attain or reach; inaccessible, unobtainable or unapproachable; unable to accomplish; beyond limit.
- n. Anything that cannot be attained.
from The Century Dictionary and Cyclopedia
- Not to be attained or gained.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. impossible to achieve
From un- + attain + -able (Wiktionary)