Man of letters is an idiom that is hundreds of years old. We will examine the meaning of the common saying man of letters, where it came from, and some examples of its idiomatic usage in sentences.
A man of letters is someone who is educated, a scholar, someone who has studied literature. The expression a man of letters came into use in the mid-1600s and is still in use today, though its popularity peaked in the 1800s and earlier 1900s. The idiom has probably fallen out of popularity because it is not gender inclusive. The word letters has been used since the 1200s to mean the profession of working in literature or writing. The plural of man of letters is men of letters.
Examples
Charles Scribner, Jr., was also a man of letters; he presided over the publishing house established by his great-grandfather in the eighteen-forties. (The New Yorker)
This novel by the foremost man of letters from Mississippi since William Faulkner takes up where a previous gripper, Camino Island (Bantam, 2017), left off. (Forbes)
I discovered during that 2015 nine-days media cycle that Barbadian man of letters and Combermere schoolmaster Frank Collymore had been quite curious half a century ago about the steups, and compiled his own taxonomy of its various meanings, which he notes are shaped both by the length of the sound, how it’s articulated, and what other facial and body language accompanies it. (Trinidad and Tobago Newsday)