At the recent annual convention of all my blog followers, I was besieged by requests to add another posting about the origins of words and sayings.
I got this one from a recent TV programme. The Dutch had a word for sellers of salves or ointments, presumably with derogatory connotations: Quacksalver. That word itself partly derives from Quacken, to boast or brag. This combination of words was in time picked up by the English, shortened and used to refer to a dubious medical practitioner – a Quack.