There are numerous synonyms for the expression "without even trying," which convey a sense of ease and nonchalance. Some of the common synonyms include "effortlessly," "easily," "with little effort," "naturally," and "involuntarily." Additionally, "smoothly," "automatically," "unconsciously," and "mindlessly" are also appropriate synonyms that emphasize the innate quality of a particular action. On the other hand, "casually," "lackadaisically," and "nonchalantly" convey a certain indifference towards the outcome of the task. Depending on the situation and the context of the sentence, one can choose any of these synonyms to reflect the effortless nature of a particular action.