malaprop
We have long been familiar with the idea of the mixed metaphor – the blend of two images to produce a sometimes hilarious result, as in that’s no skin off the sideboard, a blend of that’s no skin off your nose and there’ll be fruit on the sideboard.
A malapropism is a mistake we make with a particular word, substituting another one for it. The name for this kind of error comes from a character in a Sheridan play The Rivals which appeared in 1775. The character, Mrs Malaprop, was fond of doing this sort of thing. An example of her style is ‘He is the very pineapple of politeness’ where pineapple takes the place of pinnacle.
According to the American writer Lawrence Harrison, who coined the word in an article in the Washington Post in 1976, a malaphor is a blend of malapropism and metaphor. Examples are: He’s burning the midnight oil from both ends. It sticks out like a sore throat. It’s as easy as falling of a piece of cake. I suppose the thing that distinguishes it from a simple mixed metaphor is that both the phrases that are blended are related in meaning. It’s as easy as falling off a log and It’s a piece of cake both mean ‘this is very easy to do’.
Google Ngram charts the course of the word malaphor from its beginnings in the 1970s, with a fairly sustained but very moderate use until it takes off in 2019.