Marlee Matlin -- IF Trump's 'Retarded' Allegation is True ... My Vote Will Be My Revenge

Marlee Matlin is firing back at Donald Trump after seeing reports he allegedly referred to the deaf actress as "retarded" during her time on "Celebrity Apprentice."

Production staffers from the show claim Trump scribbled notes during board meetings, and according to The Daily Beast ... some included, "Marlee, is she retarded??" The report also said Trump would poke fun at Matlin's voice.

Matlin says, "The term is abhorrent and should never be used. The fact that we are talking about this during a very important moment in American history has upset me deeply."

Sources close to Marlee tell TMZ the actress was unaware of the allegation, but added ... Marlee never felt Trump was against her during her time on the show. She finished in 2nd place.