I once used the word "cliched" in a college term paper. My prof drew a big red line through it and wrote "no such word!" next to it. ... Now it jumps off the page at me when someone uses it as you did in your post. Has the OED accepted it in the staggeringly long span I've been out of college?
It has, Julia -- not that you need the OED's approval to use a word (and to call your prof arrogant and clueless). In 1989, just a few years after your college days, the Second Edition included the the adjective use of "cliched," citing a 1928 book by Alec Waugh (brother of Evelyn): "There is no adjective but the cliché'd deafening that can fittingly describe the tornado of noise that had welcomed the recitation."
I don't know that anyone other than your teacher ever objected to cliched. But the adjective has stirred up some controversy in its more recent, Frenchy form: "That's so cliche!" I wrote about the innovation in 2003, after a Globe reader complained about it; at the time, I said that
adjectival cliche is moving up fast. In expressions where there's a clear choice between cliche and cliched, the adjective is cliche about half the time. In most of those cases, it sneaks in by way of quotations - "It sounds cliche, but he really believed it'' (Miami Herald), or "I was brought up to love everybody, as cliche as that may sound'' (People magazine).* But it's not all spoken-word sloppiness: In the earliest citation I could find, a 1979 Washington Post review of the miniseries "Studs Lonigan,'' the writer himself says of father-son conflict, "It is an old cycle, so cliche it hurts.''
The OED was on to adjectival cliche in 1989, too, quoting the BBC's weekly, The Listener, from 1959: "The kind of fond reminiscence which comes rather too near the cliché view of human situations."
I have no idea what data I was relying on in my 2003 frequency estimate, but here's what Google Ngram Viewer has to say about so cliche vs. so cliched:
By now, I think, "so cliche" seems normal to a lot of younger speakers and writers. And I have a soft spot for it myself, as I confessed in that 2003 column, because it's such a natural choice:
Though cliche came into English as a noun, it retains its French form -- and that form is a past participle, perfectly happy to be used as an adjective. English is full of such French words, some used as nouns (divorcee, souffle, negligee), others as adjectives (passe, flambe).
Even a stickler, it seems to me, might find it in his or her heart to approve so cliche.
* There's no telling whether the source actually said "cliched" or "cliche," of course, but these instances show that the reporter and editor(s) all accepted so cliche as OK.