actionality

Actionality, also called aktionsart, is a lexical semantic notion that characterizes the inherent temporal profile of a verb's predicate. It describes how the event described by the verb unfolds in time, independent of tense, mood, or syntactic context, and how it interacts with aspect and telicity.

The classic inventory distinguishes several classes. States denote static conditions with no inherent change, such as know or own; they are typically atelic and do not present an endpoint. Activities describe ongoing, durative actions without a built-in termination, such as run or swim. Accomplishments describe durative events with a defined endpoint or culmination, such as build a house or eat an apple. Achievements denote instantaneous changes of state or sudden events that terminate the prior situation, such as recognize, win, or reach the top. Some analyses also include semelfatives for single, repeated punctiform actions like knock or sneeze.

In many languages, actionality interacts with morphology and the systems of aspect and tense. It helps explain why certain predicates are naturally aligned with perfective or imperfective readings, how duration is measured, and how events are narrativeized. In lexical semantics and event structure research, actionality provides a framework for comparing verbs across languages and for modeling how verb meaning constrains possible interpretations of time and change.