"Sick up" is a phrasal verb commonly used to describe the act of vomiting or throwing up. However, there are several synonymous phrases that can be used interchangeably with this term. Some examples include "throwing up," "vomiting," "retching," "heaving," "regurgitating," and "discharging stomach contents." These synonyms can be used to describe the physical act of expelling food or fluids from the body due to illness or other reasons. It's important to remember that while all these phrases mean the same thing, the context and severity of the situation may vary. Using an appropriate synonym can convey a more accurate portrayal of the situation.