Chambers has a few definitions for Utter. The most usual is 'to say', but there's also 'to try to pass off as genuine counterfeit money'. The clue's just a double definition one.
Thanks, Whetstone. Tent, wine, pops up occasionally. I don't think I'd ever have got the Charleston one - the film was out before I was even born! I think it's another of the very/too old clues.