activism comes from active + -ism, ultimately from Latin activus ('active, practical'), from actus, past participle of agere ('to do, drive'). Morphologically, the word is transparent: -ism is attached to the older base named in the history, so the modern form packages an inherited or borrowed stem inside a later English derivative. In modern use, the noun sense is "the practice of vigorous campaigning to bring about social or political change", which keeps the etymology connected to the word's present dictionary value rather than treating it as a merely historical label. The wider word family includes related English forms such as active, activity, act, action and derivatives such as activist, showing how the same base continues to support neighboring English vocabulary. The principal historical forms in the chain include Latin activus, Latin agere, which anchor the explanation in named linguistic material.