Learn how to say Mournfulness correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word mourn:
feel or show sorrow for the death of (someone), typically by following conventions such as the wearing of black clothes:
Isobel mourned her husband
she mourned for her friends who died in the accident
feel regret or sadness about (the loss or disappearance of something):
publishers mourned declining sales of hardback fiction
Old English murnan, of Germanic origin