The phrase 'root of trouble' implies the underlying cause or source of a problem or conflict. There are several synonyms to this phrase, including 'core issue,' 'fundamental problem,' 'originating factor,' and 'root cause.' Each of these terms highlights the necessity of identifying the underlying cause of a problem to effectively solve it. While immediate symptoms of a problem may be treated, without addressing the root of the trouble, the problem may persist and even escalate. Understanding the 'root of trouble' allows for targeted solutions and more sustainable outcomes. By using these synonyms, individuals or organizations can better communicate the need to address the root cause of a problem.