Sustainedly is an adverb that means continuously or for a long period. Some synonyms for sustainedly include persistently, consistently, continuously, enduringly, unceasingly, uninterrupted, and steadily. These words all convey an idea of actions or events that occur without interruption and continue for an extended period. Each of these synonyms can be used in different contexts but all connect to the idea of something continuing or lasting over time. For example: she sustainedly worked on her dissertation, persistently revising and rewriting until it was perfect. In summary, using different synonyms for sustainedly can add variety and richness to your writing.