Impossible to attain: unattainable goals. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "unattainable" in a sentence
"Not one of them stood back and said hang on a minute. many of the ‘targets’ (measures of public satisfaction) were unattainable from the start and as such we cannot sign up for it, thanks but no thanks."
"If he threatens that many jobs they'll vote Republican overwhelmingly making the first term unattainable anyway."
"I reply, dear Wevie, that the soul whose desires are not fixed upon the unattainable is dead even while it liveth, and that I am glad, in the midst of all my comforts, to feel myself still a pilgrim in pursuit of something that is neither house nor lands, nor children, nor health."