Column: Metaphors vs. idioms
Question: “A friend said to me that he was ‘under the weather, metaphorically speaking.’ I didn’t want to correct him, since he was sick, but I don’t think that’s right. Was that a metaphor, or was it actually an idiom?”
Great question! You are correct. Hopefully your friend is feeling better by the time you come around again to offer him some wisdom.
Metaphors and idioms are often mistaken for one another in speech in just the manner you’ve illustrated. In fact, “speaking metaphorically” is often mistakenly used when people actually mean they are “speaking figuratively.” Staying on subject, though: What is the difference between a metaphor and an idiom?
A metaphor is a rhetorical figure of speech found under the umbrella of analogy. A metaphor is formed by stating that one thing “A” is another thing “B.” Shakespeare famously used metaphors to great effect – and so for an example, we’ll turn to the Bard:
“But soft! What light through yonder window breaks? It is the east, and Juliet is the sun.”
We understand that Juliet is not, in fact, the sun. But to our teenage heartthrob Romeo, she seems a bright, incandescent, almost life-giving figure appearing at the window as the sun at dawn. How romantic.
An idiom, by contrast, is an expression with a figurative meaning that doesn’t correspond with its literal meaning. Idioms are understood intuitively by native speakers, but can be very difficult for someone learning the language. Examples of idioms in English include “couch potato,” “hit the road,” “spill the beans” and “under the weather.” Some idioms, like the phrase “Achilles’ heel,” are also metaphors, but the two are not inherently related like metaphors and similes are.
A great and simple method of determining whether a phrase is an idiom or a metaphor is to ask whether it is directly comparing two things. “In the middle of June, the blacktop was lava” is a metaphor – it directly compares very hot asphalt to lava. “To pull someone’s leg” is an idiom – we understand it figuratively to mean to tease or joke, and it fails to be a metaphor because it makes no comparison.
Just keep comparisons in mind, and you’ll be able to distinguish metaphors and idioms at the drop of a hat.