senile

Example:The youthful energy of the team was reflected in their enthusiasm.

Definition:Showing or reflecting the vigor, freshness, or innocence characteristic of youth; full of energy, vitality, and optimism.

Example:Children are generally more flexible and less constrained by habits than young adults.

Definition:At an early stage of life; not yet fully grown; not old; immature.

Example:The vigorous athlete continued to train even after the injury.

Definition:Having or showing great energy, strength, and vitality; active and vigorous.