Source : Webster's Revised Unabridged Dictionary (1913)

Mournful \Mourn"ful\, a.
   Full of sorrow; expressing, or intended to express, sorrow;
   mourning; grieving; sad; also, causing sorrow; saddening;
   grievous; as, a mournful person; mournful looks, tones, loss.
   -- {Mourn"ful*ly}, adv. -- {Mourn"ful*ness}, n.

   Syn: Sorrowful; lugubrious; sad; doleful; heavy; afflictive;
        grievous; calamitous.

Source : WordNet®

mournful
     adj 1: expressing sorrow [syn: {plaintive}]
     2: filled with or evoking sadness; "the child's doleful
        expression"; "stared with mournful eyes"; "mournful news"
        [syn: {doleful}]