cockamamie

or cock·a·ma·my

[ kok-uh-mey-mee ]
/ ˈkɒk əˌmeɪ mi /

adjective Slang.

ridiculous, pointless, or nonsensical: full of wild schemes and cockamamie ideas.

Origin of cockamamie

probably earlier than 1940–45, Americanism; in orig. sense, paper strip with an image which could be transferred to the skin when moistened, apparently alteration of decalcomania; sense “ridiculous” probably by association with cock-and-bull story, poppycock, etc.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for cockamamy

cockamamie

/ (ˌkɒkəˈmeɪmɪ) /

adjective

slang, mainly US ridiculous or nonsensicala cockamamie story

Word Origin for cockamamie

C20: in an earlier sense: a paper transfer, prob. a variant of decalcomania
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012