Reflex

Part of speech: noun

Pronunciation: /ˈɹiːflɛks/

Definitions

1. An automatic, involuntary response made by the body to a stimulus, typically without conscious thought ; a quick, immediate reaction to an event or situation that occurs without deliberation
2. A bodily movement that happens instinctively in response to a specific trigger, bypassing conscious control ; a prompt response executed without thinking when faced with sudden circumstances
3. An unthinking, spontaneous physical action in reaction to a stimulus, controlled mainly by the nervous system ; a rapid, instinctive reply to a stimulus or event occurring without prior planning

Etymology: The noun "reflex" comes from Late Latin "reflexus," the past participle of "reflectere," meaning "to bend back." The Latin verb is built from "re-," meaning "back," and "flectere," meaning "to bend," so the image at its core is of something bent back on itself or turned around. Physiology adopted the idea: a stimulus travels inward and the body's response comes straight back out, almost as if the signal had doubled over. The word's meaning in the sense of an automatic bodily response is the one most readers know, but the same Latin root gave English "reflect," and the noun "reflex" also carries a second, older sense in photography. There, it comes from the earlier noun meaning "reflection," so the light bouncing off a surface and the knee jerking under a doctor's hammer share the same bent-back ancestry.

Synonyms: response, reaction, instinct, reflex action, habit

Antonyms: deliberation, consideration, thought, intent, planning