The expression "has had enough" refers to a person feeling that they can no longer tolerate a certain situation or behavior. There are many synonyms for this expression that can be used to convey the same idea. For instance, one can say that they are fed up, had their fill, or have reached their limit. Alternatively, one can use the idiomatic expressions "throw in the towel" or "call it quits" to indicate that they are done with a particular thing. Similarly, one can say that they are at the end of their rope, the last straw broke the camel's back, or they are over it. In conclusion, the English language offers a plethora of phrases that can be used to express the idea of having had enough.