Synonyms for casually

modified

1. Accidentally

   unintentionally, by chance, inadvertently; see accidentally, haphazardly.

2. Nonchalantly

   indifferently, unconcernedly, coolly, unemotionally, impassively, reservedly, offhandedly, carelessly, informally, breezily, unceremoniously, plainly, apathetically, lackadaisically; see also carelessly, easily 1.

3. Incidentally

   aimlessly, inconstantly, randomly; see incidentally, haphazardly.