quick to act; cheerfully working; light on one's feet
Describes someone who readily gets up and does things without hesitation; often implies a willing, energetic attitude. Antonym: 腰が重い (slow to act).
See also: 腰の軽い
Antonyms: 腰が重い
He's quick to act, so he'll do anything right away.
He cheerfully joined the new project without hesitation.
Less common nuance; can imply acting too quickly without enough thought. Often context-dependent.
He's too hasty and often decides without thinking carefully.
slow to act; reluctant to get started
Literally 'one's hips are light,' an idiomatic expression comparing physical lightness to a willingness to move and act promptly.