Tác

Tác is a Vietnamese morpheme derived from Sino-Vietnamese chữ Hán 作, meaning to do, to make, or to act. In modern Vietnamese, tác is primarily used as a bound element in compound words rather than as an independent word; its sense shifts with the accompanying element and often relates to creation, influence, or function.

Common uses center on a range of nouns and nouns formed from combination with other words. Examples include tác giả (author), tác phẩm (a work or piece, such as a literary or artistic work), tác động (impact or influence), tác dụng (effect or function), and tác nhân (causal agent). Additional formations include tác phong (manner, bearing) and other terms where tác conveys the sense of making, producing, or causing.

Etymologically, tác is linked to the meaning of making or creating, and through various compounds it extends to denote a created object, an act, or an initiating factor. The word is seldom used alone in contemporary Vietnamese; it functions mainly as a productive element that forms a wide range of terms across literature, science, law, and everyday language.

Usage notes emphasize that tác carries a constructive or causal nuance, distinguishing it from words that denote mere existence or mere description. In academic and formal writing, the term frequently appears in established compounds rather than as a standalone term, and it forms part of broader expressions describing authorship, production, and effects.

See also: Sino-Vietnamese vocabulary, word formation in Vietnamese, common compound patterns with tác.