Inf. It can't be done.; I can't do it. Sorry, John. No can do. I can't sell you this one. I've promised it to Mrs. Smith.Bill: Please fix this clock today. Bob: No can do. It'll take a week to get the parts.
It's impossible; I can't do this. For example, When Bill asked me to write a speech, I told him bluntly no can do. This colloquial phrase was first recorded in 1914.