This is the 2162nd most frequent Japanese word.
有志
"有志" means "volunteer" or "someone with a will or intention to participate."
In this sentence, 有志 means 'volunteers,' referring to individuals who willingly join an effort or activity.
このプロジェクトには多くの有志が参加しています。
Many volunteers are participating in this project.
Here, 有志 highlights 'volunteers,' implying individuals who initiated planning an event out of self-motivation.
有志の人々が地域の清掃活動を計画しました。
Volunteers planned a community cleaning activity.
The word 有志 is used to describe the individual's role as a volunteer in providing aid.