Deceleratory

Part of speech: adjective

Definitions

1. Relating to the action or process of reducing speed or velocity
2. Characterized by a capacity to slow down movement or progression
3. Connected with the act of making something go slower or reducing its pace ; possessing the quality or power to decrease the speed of an object or process

Etymology: "Deceleratory" is a plain English formation, built from "decelerate" with the adjectival ending "-ory." The verb "decelerate" came first, formed in the 19th century by adding the prefix "de-" (here meaning "reduce or reverse") to "accelerate," which itself comes from the Latin "accelerare," meaning "to hasten," from "celer," "swift." So the word literally undoes an acceleration, and "decelerate" is a rough mirror image of "accelerate" with the opposite direction built in. The suffix "-ory" comes from Latin "-orius" through Old French "-oire" and "-ory," and it is used to form adjectives meaning "serving to" or "having the function of." Attaching it to "decelerate" gives a word meaning "serving to slow down." Because the suffix is productive, the form was assembled in English as needed rather than inherited from older usage, and the adjective is much rarer in print than "decelerating" or "deceleration." Its exact date of first use is uncertain.

Synonyms: slowing, retarding, diminutive, reductive, abating

Antonyms: acceleratory, speeding, hastening, quickening, expediting