n. An obvious element missing from the plot of a movie, television show, play, or book.
Is dialogue that sounds like it could be spoken by actual human beings (rather than a marketing VP) too much to ask? Can the audience NOT be insulted by having to step over gaping plotholes every third scene?
—Ty Burr, “Why 'Spider-Man' out-entertains 'Star Wars',”, May 16, 2002
1978 (earliest)
The Eddie Capra Mysteries (NBC) bring the true whodunit back to television in a style slightly sprightlier than NBC's campy "Ellery Queen." Again, though, the audience is supplied clues as the sleuth, in this case a feisty maverick lawyer, collects them. Vincent Baggetta as Capra and Wendy Phillips as his very close neighbor Lacey Brown established a sweet rapport in the program's already televised pilot show that should help sustain interest even if the mysteries run into plotholes.
—Tom Shales, “A Day-By-Day Sampling of the New Fall TV Season,” The Washington Post, September 10, 1978
This blend of plot and pothole (1909) has been a staple of the movie and TV reviewer's vocabularly since at least the late 70s.