The Oxford Thesaurus An A-Z Dictionary of Synonyms - idlyadv.

1) unproductively, lazily, indolently: She wanders about the shops, idly whiling away the hours. 2) offhandedly, unconsciously, mechanically, thoughtlessly, unthinkingly, obliviously, insensibly, indifferently: He sat quietly, his fingers idly drumming on the tabletop.