"Greedy guts" is a colloquial term that refers to someone who is excessively greedy or selfish, especially when it comes to food or money. To avoid using this term, there are various synonyms available that can be used in its place. Some commonly used alternatives include "glutton," "hog," "gourmand," "overeater," "sponger," "hoarder," "grasping," "acquisitive," "rapacious," "avaricious," and "covetous." These words can help to convey the same meaning as "greedy guts" without using an informal or potentially offensive term. Choosing the right synonym depends on the context and tone of the sentence, but there are plenty of options available.