When you go off on a tangent, you start talking about something that is unrelated to the original topic. There are many synonyms for this phrase that you can use instead. For example, you can say that someone is digressing, veering off track, or getting sidetracked. Other descriptive phrases you may want to use include losing focus, wandering off subject, or going off track. It's important to be aware of these synonyms because they can make your writing or speaking more professional and polished. So, the next time you're tempted to go off on a tangent, remember that there are many other ways to express the same concept.