In
linguisticsLinguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....
, an
agent noun (or
nomen agentis) is a word that is derived from another word denoting an action, and that identifies an entity
that does that actionIn linguistics, a grammatical agent is the cause or initiator of an event. Agent is the name of the thematic role...
. For example, "driver" is an agent noun formed from the
verbA verb, from the Latin verbum meaning word, is a word that in syntax conveys an action , or a state of being . In the usual description of English, the basic form, with or without the particle to, is the infinitive...
"drive". The endings "-er", "-or", and "-ist" are commonly used in English to form agent nouns. "Agent noun" is also used as the name of the derivational meaning (also called a
derivateme).
Usually,
derived in the above definition has the strict sense attached to it in
morphologyIn linguistics, morphology is the identification, analysis and description, in a language, of the structure of morphemes and other linguistic units, such as words, affixes, parts of speech, intonation/stress, or implied context...
, that is the
derivationIn linguistics, derivation is the process of forming a new word on the basis of an existing word, e.g. happi-ness and un-happy from happy, or determination from determine...
takes as an input a
lexemeA lexeme is an abstract unit of morphological analysis in linguistics, that roughly corresponds to a set of forms taken by a single word. For example, in the English language, run, runs, ran and running are forms of the same lexeme, conventionally written as RUN...
(an abstract unit of morphological analysis) and produces a new lexeme. However, the classification of
morphemeIn linguistics, a morpheme is the smallest semantically meaningful unit in a language. The field of study dedicated to morphemes is called morphology. A morpheme is not identical to a word, and the principal difference between the two is that a morpheme may or may not stand alone, whereas a word,...
s into derivational morphemes and
inflectionIn grammar, inflection or inflexion is the modification of a word to express different grammatical categories such as tense, grammatical mood, grammatical voice, aspect, person, number, gender and case...
al ones is not generally a straightforward theoretical question, and different authors can make different decisions as to the general theoretical principles of the classification as well as to the actual classification of morphemes presented in a grammar of some
languageLanguage may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...
(for example, of the agent noun-forming morpheme).