If you’re feeling lively, you might whistle a tune, go for a brisk jog, or strike up an amusing conversation. Lively means "active, spirited, and energetic."
Lively is an adjective derived from the noun "life," and it basically means "full of life." A lively party is exciting and entertaining. A lively person has an energetic personality, is always on alert, and prefers being active as opposed to just hanging around. Note that a "lively discussion" isn’t necessarily a happy discussion; it could be a spirited or even heated conversation where all parties are actively involved. Lively means the opposite of sluggish or dull.