nonchalant russian

• небре́жный

  careless, negligent, sloppy

  casual, offhand, nonchalant

• небре́жно

  carelessly, negligently, sloppily

  casually, offhandedly, nonchalantly

Examples

• Он просто так э́то беззаботно де́лает.

  He just nonchalantly goes about doing it.