For a plain unit of language, the word “volunteer” does a lot by itself: It can be a noun, verb and adjective. (n.) a person who voluntarily undertakes or expresses a willingness to undertake a service… a person who performs a service willingly and without pay. (adj.) 1: being, consisting of, or engaged in by volunteers; a volunteer army. 2: growing spontaneously without direct human control or supervision… growing without being seeded, planted, or cultivated by a person; springing up spontaneously: volunteer cauliflower. (v.) to offer oneself for some service or undertaking. The desire...