【Lively】 , 【animated】 , 【vivacious】 , 【sprightly】 , 【gay】 denote in common keenly alive.
【Lively】 suggests especially briskness, alertness, or energy.
【Animated】 applies especially to what is also spirited or bright.
【Vivacious】 and 【sprightly】 suggest greater lightness of spirits or quickness of wit; they apply especially to manner or language.
【Gay】 implies utter carefreeness and exuberant or overflowing spirits.