Compound adjectives

On the analogy of (6)–(9), here are some examples of right-headed compound adjectives:

(10) noun–adjective (NA): sky-high, coal-black, oil-rich

(11) adjective–adjective (AA): grey-green, squeaky-clean, red-hot

(12) preposition–adjective (PA): underfull, overactive

As with verbs, it is the type with the preposition over as its first element that seems most productive, in that new adjectives of this type, with the meaning ‘too X’, are readily acceptable: for example, overindignant, over smooth. In overactive at (12), the head of the compound is the adjective active derived from the verb act in the fashion. In structure, therefore, this adjective is not a mere string of morphemes (over + act + -ive), but rather a nested structure: [over[act-ive]].

Adjectives with a VA structure, corresponding to the VV verbs at (2), would resemble a hypothetical ‘float-light’ ‘light enough to float’ or ‘sing-happy’ ‘happy enough to sing’. One actual example is fail-safe ‘designed to return to a safe condition if it fails or goes wrong’. However, other such compounds scarcely exist, even though it is easy enough to find plausible meanings for them. This reflects the relative reluctance of verbs to participate in compounding generally in English.

All the compounds in (10)–(12) are right-headed. There are also a few compound adjectives that are not right-headed, but we will discuss them along with all headless compounds.