Unreacted

Part of speech: adjective

Definitions

1. Not having undergone or completed a chemical or physical reaction ; remaining in an original, unchanged state after exposure to reactive conditions ; describing a substance or element that has not combined or interacted with others in a process
2. Referring to material that has not participated in or been altered by a reaction ; preserving its initial composition without transformation ; indicating a component left untouched in a reactive environment
3. Characterizing a compound or element that remains untouched by any reactive change ; still in its initial form without reacting chemically or physically ; representing a substance not engaged in any transformative interaction

Etymology: "Unreacted" is a plain formation: the prefix "un-", meaning "not", attached to "reacted," the past participle of "react." The prefix goes back through Old English to Proto-Germanic, where it already carried the sense of negation, so "unreacted" simply means "not reacted." Its parts are old and native to English, even though "react" itself is a much later coinage from the Latin prefix "re-" ("again, back") and "actus," the root of "act." Because the word is built from "un-" and "reacted," its meaning follows directly from them: a substance that has not undergone a reaction and remains in its original state. Chemists use it most often when describing leftover starting materials in a reaction mixture, which are recovered or measured rather than transformed.

Synonyms: inactive, uncombined, residual, unused, untouched

Antonyms: reacted, combined, active, used, converted