An Australian dictionary has chosen "milkshake duck" as its word of 2017, though after the announcement most people said they had never heard of the term.

Milkshake duck is a term born in the twittersphere that describes an overnight social media sensation whose viral support rapidly dissolves with closer scrutiny.

The official definition from Macquarie Dictionary is: A person who is initially viewed positively by the media but is then discovered to have something questionable about them which causes a sharp decline in their popularity

Australia's response on Monday was that most had never heard of the term that originated in 2016.

Macquarie's committee said the milkshake duck phenomenon was familiar to Australians, even if the term was not.