"Tsk, tsk, tsk" is an onomatopoeia, that is, the written reproduction of a noise that people usually make with their mouth in an act of disapproval.
This expression is often accompanied by gestures, such as shaking the head in denial or disapproval.
Learn more about the meaning of Onomatopoeia.
It is an expression well known by readers of comic book magazines, comic books in general and other types of drawings.
O "tsk, tsk, tsk” still serves to “materialize” other feelings, such as disappointment and failure.
Example: "Tsk, tsk, tsk… You should be ashamed!”
Tsk it can also be used, in a literary context, to express one person's admiration for another, usually related to passion or love.
In this sense, the "tsk” would be an onomatopoeia for the “noise” made with the blink of the lover's eyes. This onomatopoeia is usually seen in cartoons or comic books.
In the language of social media on the internet or in text messages, the "tsk” is known as an acronym for "I'm fed up", that is, the person is not in the mood to talk at that moment.