deadjectival

Deadjectival is a linguistic term used to describe a word that is derived from an adjective. In morphology, deadjectival formations are created by affixation or other derivational processes that take an adjective as the base and yield a new word, typically with a distinct part of speech such as a noun or a verb. The label emphasizes the source adjective rather than the word’s final category.

Deadjectival nouns are common in English. Examples include darkness, redness, brightness, softness, and length, all of which originate from the corresponding adjectives dark, red, bright, soft, and long. These nouns often denote a quality, state, or measure associated with the adjective. The process is typically productive with suffixes such as -ness, -ity, or -th.

Deadjectival verbs are another major category. They are formed from adjectives by affixation, most often with the suffix -en, as in darken (to become dark), brighten (to become bright), redden (to become red), and soften (to become soft). Such verbs encode a change of state related to the adjective’s meaning.

Cross-linguistically, deadjectival derivation is a common mechanism for expanding a lexicon, and similar processes are found in languages with rich suffixal morphology. The specific affixes and productivity vary by language, but the basic idea—building new words from adjective bases—remains widespread.

In usage, the term deadjectival is primarily a descriptive label used in linguistic analysis to organize word formation by origin. It does not imply a particular meaning beyond the relationship to the source adjective.