An agent noun is a noun that refers to a party performing some action. In some definitions of this part of the English lexicon, the noun must be derived from the action being performed. For example, the word “editor,” derived from the verb “edit,” is an agent noun.
The syntax of the agent noun is usually relatively straightforward. In most cases, to form this specific type of noun, English speakers or writers simply add an "–er" suffix. In some rare cases, this can change slightly. For example, the noun “hanger-on” is someone who hangs on. Here, the –er is added at the end of the verb, but not at the end of the entire noun.
It’s important for beginners in the English language to understand that, although the English lexicon includes a large number of agent nouns, not every action verb corresponds to an agent noun. Controversies exist among linguists over forming a noun like “partier” referring to someone who enjoys parties, which have entered the spoken language relatively recently.
Another potential problem for English-language beginners dealing with agent nouns is the use of the particular suffix to form the word. In most cases, as mentioned above, speakers and writers use the simple –er suffix. In some other examples of these sorts of nouns, like actor, inspector and emperor, an –or suffix is used instead. This can be confusing to those who are trying to learn the right spellings for agent nouns.
In addition to these suffixes for agent nouns, a few others often apply as well. One primary example in the “gendering” of agent nouns in English to distinguish between male and female subjects. While most nouns in English don’t have gender indicators, some agent nouns may. For example, the noun “actor” is often changed to “actress” when it references a female. The suffix “ess” is the most common form of this type of gendered noun. This type of usage was more widespread in the past, but may still be heard with certain words.
Agent nouns may also end in “ist.” Many of the most common agent nouns that use this suffix in English correspond to a person’s political ideas or other principles. Others refer to a person’s occupation.
For example, the noun “communist” is a prominent example, where the “ist” suffix shows a person’s political leanings. The word “alienist,” most common in British English, refers to a specific medicolegal occupation. Another familiar noun in British English is “mentalist” where the word treads middle ground between an occupational label and a political, spiritual or psychological one: a mentalist refers to someone who is an advocate or practitioner of various “mental sciences.”