The onomatopoeic expression "tsk-tsk" is usually used to denote disapproval or disappointment, often accompanied by a clicking sound produced by the tongue against the roof of the mouth. However, there are many synonyms for this sound that can be used in different contexts. For example, clucking, tutting, and shaking one's head are all similar gestures that can convey a similar message of negativity. Similarly, "well, well," "tsk," and "oh dear" can all be used to indicate disapproval or concern. It's important to choose the right expression based on the situation and the relationship between the speakers, as some of these synonyms may come across as rude or dismissive.