Samuel A. Adams, a defendant in retired Army Gen. William C. Westmoreland's libel suit against CBS three years ago, filed a $75 million suit against New Yorker magazine writer Renata Adler yesterday for her articles and book on the 1985 trial.

That trial ended in a settlement before the case was to go to the jury.

Adams, a former Central Intelligence Agency employe who was a consultant on the "CBS Reports" documentary program that provoked Westmoreland's suit, said in his complaint that Adler's two articles in The New Yorker and her book for Alfred A. Knopf libeled him by portraying the television show as "dishonest" and accusing Adams of trying to persuade CBS witnesses to lie in court.

Roslyn A. Mazer, a Washington attorney who defended Adler's stories for The New Yorker in another libel suit by media consultant Greg Rushford, said neither she nor The New Yorker had seen the complaint and they were not prepared to comment.

Rushford's suit was dismissed last month by U.S. District Court Judge Albert V. Bryan Jr., who said that the Alder article concerning Rushford "is no more than the author's opinion, albeit scathingly critical, of the media, libel trials, libel lawyers and libel laws."

Rushford has appealed.