Dead Metaphor

A dead metaphor is a metaphor which has lost the original imagery of its meaning due to extensive, repetitive popular usage. Because dead metaphors have a conventional meaning that differs from the original, they can be understood without knowing their earlier connotation. Dead metaphors are generally the result of a semantic shift in the evolution of a language. A distinction is often made between those dead metaphors whose origins are entirely unknown to the majority of people using them (such as the expression "to kick the bucket") and those whose source is widely known or symbolism easily understood but not often thought about (the idea of "falling in love").

There is debate among literary scholars whether so-called "dead metaphors" are dead or are metaphors. Literary scholar R.W. Gibbs noted that for a metaphor to be dead, it would necessarily lose the metaphorical qualities that it comprises. These qualities, however, still remain. A person can understand the expression "falling head-over-heels in love" even if they have never encountered that variant of the phrase "falling in love." Analytic philosopher Max Black argued that the dead metaphor should not be considered a metaphor at all, but rather classified as a separate vocabulary item. If the verb "to plough" retained the simple meaning of "to turn up the earth with a plough," then the idea of a car "ploughing through traffic" would clearly be a metaphor. The expression would be a comparison between the motion of the plough cutting through the soil and a car speeding through traffic. In order to understand it, one would need to grasp the comparison. However, "to plough" has taken on an additional meaning of "to move in a fast and uncontrolled manner," and so to say that a car "ploughed through the traffic" is a literal statement. No knowledge of the original metaphorical symbolism is necessary to understanding the statement.