The phrase "weakest entry" refers to the least strong or powerful option among a group of choices. It suggests that this particular option is the least effective or least likely to succeed compared to others. Full definition
Sure, there are a few weak entries, but I don't think of this franchise as a series of movies anymore. (rottentomatoes.com)
It's unclear why those movies, box office hits but among the creatively weaker entries in that studio's canon, would qualify Letterman for taking the helm on such a high - profile project. (dvdizzy.com)
Second, it is directed by Joe Roth, whose credentials include some very weak entries, most notably, Christmas with the Kranks, America's Sweethearts, and Revenge of the Nerds Part II. (qwipster.net)