1.
padded sleeveless vest
A short, sleeveless, padded jacket worn over other clothing for warmth. It is best known today as the red vest traditionally given to someone celebrating their 還暦 (60th birthday).
ちゃんちゃんこを着る。
To wear a padded vest.
ちゃんちゃんこ is a short, sleeveless padded jacket worn for warmth over other clothes, traditionally by children and the elderly.
Cultural note
A red ちゃんちゃんこ is the traditional gift for someone celebrating 還暦 (their 60th birthday), since red symbolizes rebirth as the person begins a new 60-year cycle of the zodiac.