An intellectual is a person who engages in critical thinking, research, and reflection about the reality of society, and who proposes solutions for the normative problems of society. Coming from the world of culture, either as a creator or as a mediator, the intellectual participates in politics, either to defend a concrete proposition or to denounce an injustice, usually by either rejecting or producing or extending an ideology, and by defending a system of values.
The term "man of letters" derives from the French term belletrist or homme de lettres but is not synonymous with "an academic". A "man of letters" was a literate man, able to read and write, as opposed to an illiterate man in a time when literacy was rare and thus highly valued in the upper strata of society. In the 17th and 18th centuries, the term Belletrist(s) came to be applied to the literati: the French participants in—sometimes referred to as "citizens" of—the Republic of Letters, which evolved into the salon, a social institution, usually run by a hostess, meant for the edification, education, and cultural refinement of the participants.
In the late 19th century, when literacy was relatively common in European countries such as the United Kingdom, the "Man of Letters" (littérateur) denotation broadened to mean "specialized", a man who earned his living writing intellectually (not creatively) about literature: the essayist, the journalist, the critic, et al. Examples include Samuel Johnson, Walter Scott and Thomas Carlyle. In the 20th century, such an approach was gradually superseded by the academic method, and the term "Man of Letters" became disused, replaced by the generic term "intellectual", describing the intellectual person.
The earliest record of the English noun "intellectual" is found in the 19th century, where in 1813, Byron reports that 'I wish I may be well enough to listen to these intellectuals'.