What is another word for happen to do something?
Pronunciation: [hˈapən tə dˈuː sˈʌmθɪŋ] (IPA) 
When you want to describe an activity or action that someone did by chance or accidentally, you can use different synonyms for the phrase "happen to do something". Some alternatives you can use are "unintentionally", "inadvertently", "by accident", "unexpectedly" and "by chance". These expressions suggest that the action was not deliberate or planned, but rather occurred unexpectedly. For instance, you can say "I inadvertently spilled coffee on my dress" to express that you accidentally spilled coffee without intending to. Similarly, using an alternative phrase can add a different tone or nuance to your speech and help you avoid repeating the same words over and over again.
