There are several synonyms for the phrase "feed up" that can be used to convey a similar meaning. One commonly used synonym is "sick and tired," which indicates a feeling of annoyance or frustration. Another option is "fed up," which means the same thing but with a slightly stronger emphasis. Other synonyms include "exasperated," "irritated," and "bored stiff." These phrases can be used interchangeably with "feed up" depending on the context and tone of the conversation. It's important to choose the right synonym based on the situation and the emotions being conveyed in order to accurately express one's feelings.