If it looks like a duck and quacks like a duck, it must be a duck - or could you be dealing with a 'quack'? Find out by reading this Word of the week by Tim Bowen.
Quack is an onomatopoeic word, meaning that it imitates the word it describes, in this case the sound made by a duck.
As a noun, it also has the meaning of either a doctor who is not very good or someone who cheats people by pretending to be a doctor. This use of quack is believed to derive from a 17th century Dutch term quacksalver, used to describe a person who boasted about his remedies and their effectiveness.
Today, apart from describing a doctor with bogus qualifications who is not really a doctor at all, it can also be used in informal British English to describe any doctor, but with a slight implication that the doctor may not be able to provide a solution because he or she is not a particularly good doctor, as in, ' I’m not feeling too good. I think I’d better go and see the quack'.