An agentive ending in the English language is the use of the suffix -er, -or, -ist, or -ian at the end of a verb in order to create a noun meaning "someone who does the action the verb describes." Examples include provider (from provide) and builder (from build).

Sometimes speakers add an agentive ending to verbs with which agentive endings are not generally associated. An example of this sort of lexical invention is suicider (from suicide), a usage which is attributed to George W. Bush, as in the following quote: "[Saddam Hussein] was a threat because he funded suiciders" [1]. This usage has a more specific meaning than most agentive endings since it is not meant to describe any person who commits suicide, but rather only one who does so with the intent to kill other people as well.

Examples of words with -ist and -ian endings include pianist and librarian.

See also: Bushism, gerund