What is "tut-tutted"

Usage examples of "tut-tutted".

He tut-tutted sadly when he learned that "Captain Sheffield's" license to pilot had been suspended.

As the senior engineers shook their heads and tut-tutted over the damage, critiquing Hollister's emergency repairs, Sassinak found herself increasingly tart with her inquisitors.

On top of this fact was another: that the advanced military minds who designed this battleship would have tut-tutted in horror if they had been asked how the crew was to defend it against a boarding party.