American English: a publicist or press agent. Came into usage around 1946, but the etymology is obscure. It could be a derivation of "flak," as a public relations person would certainly be a flak catcher. Ed Boyer of the Los Angeles Times notes that the veterans of WW2 and Korea he worked with in the newsroom dismissed calls from publicists as "just so much flak," treating reporters and their questions as if they were incoming enemies.