Impossible to overcome; insurmountable: insuperable odds. (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 "insuperable" in a sentence
"He recalled the insuperable aversion the old man had ever entertained to approach of even make mention of the spot, and greatly did he blame himself for having persisted in offering a violence to his nature, the extent of which had been made so fearfully obvious."
"Do you happen to think of any more 'insuperable' obstacles, my dear sir? ""
"But we also know that unity can be and has been attained among men of the most disparate origins, that differences of race, of religion, of culture, of tradition, are no insuperable obstacle to the coming together of peoples."