The word "flaggingly" refers to something that is done with decreasing energy or enthusiasm. Some synonyms for this word include wearily, sluggishly, lethargically, listlessly, and tiredly. These words all suggest a lack of vitality or vigor, and convey a sense of fatigue or exhaustion. Other possible synonyms for "flaggingly" might include languidly, lackadaisically, apathetically, or halfheartedly. These words all describe a sluggish or indifferent approach to a task or activity, and suggest a lack of interest or enthusiasm. Whether you're looking for a way to describe your own efforts or the actions of someone else, there are plenty of synonyms for "flaggingly" that can help you capture the right tone or mood.