Not to be believed; incredible: unbelievable luck. (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 "unbelievable" in a sentence
"Outside court, Mr. Boyland expressed relief and thanked his legal team and supporters, repeating the word "unbelievable" three times."
"It produces heroic strivings for evidence to prove that the unbelievable is the only thing that can be believed ....."
"A member of the rebels fighting forces loyal to Libyan leader Moammar Gadhafi says his group is concerned that the international community has been unable to stop what he describes as the unbelievable atrocities being committed by Gadhafi forces against unarmed Libyans in Misrata and Zawiya."