EXCLUSIVE

One of Bill O'Reilly's former coworkers isn't standing for what she considers his trash talk about FOX paying sexual harassment settlements -- she's filed a defamation suit against him.

Former FOX News anchor Laurie Dhue is suing Bill for comments he made after FOX News paid settlements to 5 women ... including Laurie, who reportedly got over $1 million. In her suit, Laurie takes umbrage with Bill's statement that he was fired over "completely unfounded claims."

Further, she says his claim, during a Matt Lauer interview, that he "never mistreated anyone on [his] watch in 42 years" is not only a lie ... it's also damaging her career. As she puts it, no one's going to hire a journalist who's been labeled a liar.

And there's this bizarre aside -- Laurie says her image has been used in online ads for male enhancement pills, which also feature O'Reilly. Seems like she's saying she's been unnecessarily dragged into the penis pill market, due to her association with O'Reilly.

A former junior producer at FOX, Rachel Bernstein, filed a similar suit in December against O'Reilly.