reformer
🇺🇸
/rɪˈfɔːrmər/
🇬🇧
/rɪˈfɔːmə(r)/
Someone who tries to change and improve something, like laws or habits, to make them better.
The reformer worked hard to change the laws to make society better.
改革者は社会をより良くするために法律を変えるために一生懸命働いた。