Matt Damon Says He Stopped Using Homophobic F-Slur Just Recently

Matt Damon says he just recently stopped using the homophobic f-word slur -- this after his own daughter had to put him in check ... with a detailed thesis of sorts on why it's bad.

The actor did a wide-ranging interview with The Sunday Times that was published Sunday, and among the many topics discussed on how the Hollywood landscape is changing (for the worse, Matt seems to think) ... this one was brought up in the same breath.

He says he put the f-word away for good in recent months, explaining he didn't think of it much as a slur when he was growing up, adding ... "The word that my daughter calls the 'f-slur for a homosexual' was commonly used when I was a kid, with a different application."

He goes on to say that he made a joke using the word in front of one of his 3 daughters, -- who range in age between 10 and 15 -- and they actually protested his usage of it.

Matt says, "She left the table. I said, 'Come on, that's a joke! I say it in the movie Stuck on You!' She went to her room and wrote a very long, beautiful treatise on how that word is dangerous. I said, 'I retire the f-slur!' I understood."

The scene Damon is referring to happens toward the end of the raunchy 2003 comedy -- in which he and Greg Kinnear play bros who are joined at the hip, literally. The word comes up in its shortened form as a musical montage starts to play after they've been separated.

There's a lot more in Damon's ST interview -- including a hot take that anyone, really, with wit could've played Iron Man ... not just RDJ. That's a whole other can of worms, though.