overflowing with vitality; exuberant; effervescent
Describes a person, atmosphere, or group that is brimming with energy and lively spirits. Often used in written or slightly formal contexts.
The audience was captivated by his speech overflowing with vitality.
The new employees' exuberant demeanor brightened up the workplace.
活気 is a common noun meaning 'vitality' or 'energy'; 活気横溢 is a more emphatic, literary compound expressing that vitality is overflowing.
元気 is the everyday word for 'energetic' or 'healthy'; 活気横溢 is more intense and formal, often describing an atmosphere or collective mood.
A four-character compound (yojijukugo) combining 活気 (vitality) and 横溢 (overflowing). The exact origin is uncertain, but it follows a common pattern of Sino-Japanese compounds.