Off-handedly is an adverb that means to do something in a casual or unprepared manner. Some synonyms for this word include nonchalantly, unconcernedly, indifferently, carelessly, and casually. These words can all be used in place of off-handedly to convey a similar meaning. Other synonyms that have a slightly different connotation include flippantly, dismissively, and cavalierly, which can indicate a lack of seriousness or respect for a situation or person. Choosing the appropriate synonym depends on the context and tone of the sentence, but these words can help add variety to your writing and convey different shades of meaning.