tut-tut
Concise Oxford English Dictionary © 2008 Oxford University Press:
tut-tut /tʌtˈtʌt/ (also tut)
▶exclamation expressing disapproval or annoyance. ▶verb (tut-tuts, tut-tutting, tut-tutted) make such an exclamation.
– origin C16: natural utterance.
'tut-tut' also found in these Oxford entries:

