Source : Webster's Revised Unabridged Dictionary (1913)

Peaceful \Peace"ful\, a.
   1. Possessing or enjoying peace; not disturbed by war,
      tumult, agitation, anxiety, or commotion; quiet; tranquil;
      as, a peaceful time; a peaceful country; a peaceful end.

   2. Not disposed or tending to war, tumult or agitation;
      pacific; mild; calm; peaceable; as, peaceful words.

   Syn: See {Peaceable}. --{Peace"ful*ly}, adv.. --
        {Peace"ful*ness}, n.

Source : WordNet®

peacefully
     adv : in a peaceful manner; "the hen settled herself on the nest
           most peacefully"