"gave me a cockamamie reason for not going"
"wore a goofy hat"
"a silly idea"
"some wacky plan for selling more books"
给我一个不去的愚蠢理由。
That is the most cockamamie plan I've ever heard.这是我听过最疯狂的计划,行不通的。
He gave me a cockamamie reason for not going there.他给了我一个不去那儿的复杂的(假的?)原因。