The phrase "redemption arc" refers to a character in a story going through a journey of change and growth, often from being a villain or troubled person to becoming a hero or a better version of themselves. Full definition
Those moments, though, have little to nothing to do with the plot, which gives us a tougher villain and two, interconnected redemption arcs for Deadpool. (markreviewsmovies.com)
Though the cast is brilliant all around, the versatile Sam Rockwell still manages to stand out, even if Dixon's hasty redemption arc feels unearned. (slate.com)
Some might find the main character abrasive beyond redemption but the movie sells that redemption arc adequately. (metacritic.com)