Frown

A frown was a facial expression which, according to the Twelfth Doctor, most people displayed when they did not understand something. (TV: The Pilot)

Meeting his fifth incarnation, the Tenth Doctor nostalgically recalled his "frowny face". (TV: Time Crash)

According to Donna Noble, "dad-shock" involved "blokes with pushchairs and frowns". (TV: The Doctor's Daughter)