The antonyms for the word "un-troubling" would be troubling, difficult, problematic or worrisome. An antonym is a word that has the opposite meaning of another word. The word "un-troubling" is often used to describe non-problematic situations or circumstances that are not causing any anxiety or stress. Conversely, synonyms for "un-troubling" include words like comforting, relaxing, soothing, and easy. In order to communicate effectively, it is important to understand the meaning of a word, and to be familiar with its antonyms, synonyms, and related words.