Hyphenate compound adjectives before a noun to indicate that the adjectives should be read as a unit, thereby avoiding ambiguity.
Although hyphens are only sometimes needed to avoid misunderstanding, hyphenate compound adjectives even when confusion is unlikely.
However, do not hyphenate compound adjectives in which the first element is an adverb ending in either ly or in y.
Similarly, do not hyphenate compound adjectives in which the first element is a comparative (such as less) or a superlative (such as most).
 | small-city mayors [as opposed to city mayors who are small] |
| a popular-music producer [as opposed to a music producer who is popular] |
Although hyphens are only sometimes needed to avoid misunderstanding, hyphenate compound adjectives even when confusion is unlikely.
| a little-discussed problem |
| a low-prevalence phenomenon |
| a well-meaning intervention |
However, do not hyphenate compound adjectives in which the first element is an adverb ending in either ly or in y.
| a compellingly argued paper |
| a highly detailed research proposal |
| a very engaging argument |
Similarly, do not hyphenate compound adjectives in which the first element is a comparative (such as less) or a superlative (such as most).
| a less complicated suggestion |
| the most cited research paper |
Recommended citation:
«Compound adjectives» [en línia]. A: Llibre d’estil de la Universitat de Barcelona. Barcelona: Universitat de Barcelona. Serveis Lingüístics. <https://www.ub.edu/llibre-estil/criteri.php?id=2273> [consulta: 21 gener 2026].