Bolix up is a phrase used to refer to situations where someone makes a mistake or blunders in their actions. There are many synonyms that can be used in place of bolix up, depending on the context and severity of the mistake being made. Other phrases that can be used instead of bolix up include mess up, blunder, bungle, goof, flub, and fumble. These phrases have similar meanings and are used to describe cases where a person has made a mistake or failed to achieve their intended goal. It is important to use the appropriate synonym depending on the context to ensure clear communication.