Liveliness, n.
Etymology: [From Lively.]
1. The quality or state of being lively or animated; sprightliness; vivacity; animation; spirit; as, the liveliness of youth, contrasted with the gravity of age. B. Jonson.
2. An appearance of life, animation, or spirit; as, the liveliness of the eye or the countenance in a portrait.
3. Briskness; activity; effervescence, as of liquors.
Syn. -- Sprightliness; gayety; animation; vivacity; smartness; briskness; activity. -- Liveliness, Gayety, Animation, Vivacity. Liveliness is an habitual feeling of life and interest; gayety refers more to a temporary excitement of the animal spirits; animation implies a warmth of emotion and a corresponding vividness of expressing it, awakened by the presence of something which strongly affects the mind; vivacity is a feeling between liveliness and animation, having the permanency of the one, and, to some extent, the warmth of the other. Liveliness of imagination; gayety of heart; animation of countenance; vivacity of gesture or conversation.
Shades of meaning
Fernald has no entry of its own for liveliness; he lists it under pertness.
Where he writes about it:
Liveliness and sprightliness are pleasant and commendable; smartness is a limited and showy acuteness or shrewdness, usually with unfavorable suggestion; pertness and sauciness are these qualities overdone, and regardless of the respect due to superiors. — from pertness