Untroublesome is a word that describes something that does not cause any difficulty or problems. However, there are numerous synonyms that can replace this word to convey the same meaning, such as hassle-free, easygoing, effortless, unproblematic, painless, simple, smooth, trouble-free, and uncomplicated. These words can be used interchangeably depending on the context of the sentence. For instance, you can use "effortless" to describe a task that is easily accomplished or "uncomplicated" to refer to a situation that does not require too much thinking or complexity. These synonyms can help to add variety and precision to your written or spoken language.