Not workable, especially not capable of being put into practice successfully; not practicable: an unworkable scheme. (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 "unworkable" in a sentence
"Instead of being reinstated, which she called unworkable, Sands wanted two more years of pay."
"This is due to an architecture that was unworkable from the start and everyone knew it."
"But he described as unworkable a system where school boards spend money that supervisors must collect through taxes."