Open up is a commonly used phrase that can be replaced with several synonyms. For instance, "reveal" is a synonym that can be used to replace the phrase in situations where one is disclosing confidential information to someone else. "Unfold" can also be used in place of open up in cases where a story is being told. "Expand" is another synonym that can be used when discussing a situation that is growing and becoming more significant. Other synonyms include "disclose," "display," and "expose." They all mean to reveal something that was previously hidden or unknown. By using these synonyms, one can add variety to their writing and speaking and avoid repetition of the phrase "open up".