The Mistubishi Pajero sold dismally in Spain, where "Pajero" is slang for 'masturbator.'

Toyota Fiera was contoversial in Puerto Rico, because 'fiera' translates to "ugly old woman."

Rolls-Royce tried selling their "Silver Mist" model, but few bought it. Probably because it comes out as "Silver Animal Droppings" in German.

The Pinto didn't sell too well either, i believe mostly in Brazil.Reason?
Pinto = slang for "small penis" in Portugese

You would think somebody in Marketing would catch on...

The Chevy Nova story is possibly apocryphal, despite the wide coverage of it and mention in plenty of books.

For more of these, I'd reccomend Brad Haig's Brand Failures: The Truth About the 100 Biggest Branding Mistakes of All Time