April Ryan Slams Omarosa Saying She Used Ghostwriter

April Ryan is throwing some serious shade at Omarosa ... saying she never put pen to paper because she used a ghostwriter.

Ryan -- who has reported at the White House for more than 20 years -- bashes Omarosa for her secret recordings and being a backstabber.

April says her upcoming book, "Under Fire: Reporting from the Front Lines of the Trump White House," unlike Omarosa's book, is the real deal.

As for bowing down to Trump before she broke ranks ... April says O shouldn't wait for invites to the church social anytime soon.