quick-reaction

The compound "quick-reaction" is a modern military and organizational term built from two deeply rooted English words. "Quick" originates from the Old English cwic, meaning "alive," a sense that evolved to signify mental alertness and then physical speed. "Reaction" comes from the Latin reagere, via re- (back) and agere (to do, drive), literally meaning "to act in return." The logic of the compound is transparent: it describes a capability or unit designed to "act back" with "lively" speed, directly linking the ancient concepts of vitality and responsive action to the modern need for immediate countermeasures.

Structure: quick (fast) + reaction (response) - quick: From Old English cwic (alive, living, lively), of Germanic origin. In this compound, it functions as an intensifying adjective meaning "fast, rapid." - reaction: From the base word react (re- "again, back" + act "do") + the noun-forming suffix -ion. It functions as the core noun meaning "a response to a stimulus."