Metaphor and Idioms: Motivation, Meaning and Use

An idiom is a conventional expression whose established meaning is not fully predictable from an ordinary combination of its parts. Some idioms have readily interpretable imagery; others offer little help to a learner who has not encountered them before. Metaphorical motivation concerns how an image can make an established meaning intelligible, without necessarily making that meaning predictable in advance.

This article develops the distinctions introduced in Idiomatic, Literal and Figurative Communication. Its central question is not simply whether an idiom is metaphorical, but what its words, conventional meaning and particular use each contribute. Kroeger's introduction to semantics treats idioms as an important qualification to the principle that complex meanings can be built from their components.

Motivation is different from prediction

Once a learner knows that “spill the beans” concerns revealing a secret, the image of something contained becoming publicly exposed may offer a memorable interpretation. It does not follow that someone who knows only “spill” and “beans” could reliably infer the conventional meaning. Many stories could be invented from those two words.

Nor does such an interpretation establish the expression's historical origin. An attractive explanation of an idiom's imagery is a present-day analysis unless documentary evidence establishes its etymology. A wiki entry should label these different claims separately.

The same principle applies to the pressure imagery associated with anger expressions. Kövecses discusses research in which people were asked to form mental images of idioms and answer questions about them. In his account, the resulting regularities support connections between certain anger expressions and a pressurised-container model. An elicited imagery task is not direct evidence that everyone spontaneously forms the same image during ordinary conversation.

Features that can vary independently

Feature	Question to ask	Why the distinction matters
Conventionality	Is this an established expression for the relevant community?	A novel metaphor can be intelligible without being an idiom.
Transparency	How readily does the imagery suggest the familiar meaning?	An expression can become easier to explain after its meaning has been learnt.
Familiarity	Has this reader encountered this expression before?	A conventional idiom can still be unfamiliar to a particular speaker.
Flexibility	Which grammatical or lexical changes preserve its idiomatic use?	Knowing a paraphrase does not establish which substitutions are acceptable.
Contextual function	Is it reassurance, criticism, humour, narration or something else?	The same conventional meaning can perform different social work.

These dimensions are useful questions for description, rather than a scoring system that assigns every idiom a fixed position. Claims about familiarity or acceptability should identify the speakers, dictionaries or data on which they rest.

Literal use, idiomatic use and reactivated imagery

Consider three constructed situations involving “on thin ice”. In the first, a walker is crossing a frozen pond. In the second, a manager warns that another missed deadline will put someone's position at risk. In the third, a writer extends the warning by adding that cracks are already appearing.

The first situation supports a literal reading. The second supports a familiar figurative description of insecurity or danger. The third deliberately develops the physical scene to add a further implication. Context determines what the expression is doing, and an extended image can add meaning beyond a short dictionary paraphrase.

An analyst should therefore retain the surrounding passage. Replacing all three examples with “in danger” would conceal the literal setting in the first and the creative development in the third. Conversely, assuming that every idiomatic use contains a detailed imagined frozen landscape would go beyond the evidence.

Idioms across languages

An equivalent communicative purpose does not require an identical source image. Kövecses distinguishes wording, literal meaning, figurative meaning and conceptual metaphor when comparing English and Hungarian expressions. His analysis shows why a close translation at one level need not preserve the others.

For a translated idiom, record the original wording, a labelled literal gloss, the established meaning, and the translation selected for the present passage. A gloss preserves lexical information; a natural translation may preserve tone or function while changing the image. Neither should silently stand in for the other.

Metaphor Across Languages and Cultures provides documented examples. Learning Metaphor in a Second Language discusses why comprehension, retention and later production are separate outcomes in learning research.

Building a useful idiom entry

A strong entry begins with an attested form and a source. It then gives a contextual example, identifies its register where the evidence permits, and explains its established meaning. A proposed metaphorical reading belongs in a separate explanation, with enough detail for the reader to assess it.

For a constructed teaching example, say that it is constructed. For a historical origin, cite historical evidence rather than a memorable anecdote. For variation, record which form occurs in which source instead of silently normalising all examples into one preferred wording.

This approach is particularly useful for descriptions of movement and constraint. Expressions involving being stuck, held back or carried along may be close in broad meaning while differing in agency, direction and the location of an obstacle. An idiom collection can preserve those differences without turning them into fixed interpretations of an individual's experience.

Related pages

• Idioms A-Z
• Metaphor Identification and Corpus Research
• Metaphor and Polysemy: How Words Acquire Related Meanings
• Mixed Metaphors and Coherence
• Metaphor Research Library