1. uncalled for; lacking good reason; unwarranted.
  2. given or done free of charge.

Examples of gratuitous in a sentence:

  • Even though I had been looking forward to seeing the movie, I walked out of the theater after thirty minutes because of so much gratuitous foul language.
  • Since her son had already served his hours of community service for the vandalism, Selena thought that the school’s additional punishment was gratuitous.