Cheerfulness is a bright and happy manner. Unfailing cheerfulness, forced cheerfulness.
It is a manner rather than a feeling, which is why it can be kept up deliberately. Cheerfulness in bad circumstances is a kindness done to everybody else.
1nouncheerfulnessA bright and happy manner.
“Her cheerfulness held the whole ward together.”
cheerfulness is a manner.
From cheerful, from cheer, which first meant the face and only later the mood on it.
Middle English
cherefulnes
English, today
cheerfulness
From Middle English cherefulnes; equivalent to cheerful + ness.
Etymology from Wiktionary, CC BY-SA