noun
A person who provides assistance or support, often in a formal or organizational context. Neutral term for someone who helps another.
彼は研究の補助者として雇われた。
He was hired as a research assistant.
補助者がいると作業がはかどる。
Having a helper makes the work go faster.
支援者 means 'supporter' in the sense of providing backing or aid, often financial or moral, while 補助者 focuses on direct assistance in tasks.
Compound of 補助 (hojo, 'assistance') + 者 (sha, 'person'). The reading is straightforward on'yomi.