Slang Ludicrous; nonsensical: gave me a cockamamie reason for not going. (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 "cockamamie" in a sentence
"Pace Webster's Third [XV,3], but including the word cockamamie in a Yiddish lexicon is questionable, as is the definition given."
"These are the kind of cockamamie questions that lead to life deficit disorder."
"Since Crist's labeling a while back of these efforts as "cockamamie", it appears that he has logged a full workday recently enough to understand that those cockamamie efforts are finally coming to fruition."