fight-or-flight

adjective

ˈfīt-ər-ˈflīt 

: relating to, being, or causing physiological changes in the body (such as an increase in heart rate or dilation of bronchi) in response to stress

epinephrine is a fight-or-flight hormone

a fight-or-flight reaction

Examples of fight-or-flight in a Sentence

Recent Examples on the Web

In this state, the nervous system’s fight-or-flight response takes priority, inhibiting relaxation, pleasure and trust, which make for the key ingredients of romantic connection. —Mark Travers, Forbes.com, 9 Sep. 2025

Under extreme stress, the fight-or-flight hormones aggressively trigger the endogenous opioid system, which greatly reduces the pain. —Dr. Sanjay Gupta, CNN Money, 26 Aug. 2025

Acute stress can suppress appetite when the body enters fight-or-flight mode and produces catecholamines, which are stress-response hormones.34 4. —Laura Schober, Health, 21 Aug. 2025

Snakes are a central part of this group of animal villains, but while boa constrictors or venomous rattlesnakes have earned it, not all snakes warrant a fight-or-flight response. —Irene Wright, Miami Herald, 6 Aug. 2025

Word History

First Known Use

1973, in the meaning defined above

Rhymes for fight-or-flight

• acolyte
• aconite
• allanite
• alunite
• amberlite
• ammonite
• amorite
• amphitrite
• analyte
• anchorite
• andesite
• anhydrite

Medical Definition

fight-or-flight

adjective

ˌfī-tər-ˈflīt

: relating to, being, or causing physiological changes in the body (such as an increase in heart rate or dilation of bronchi) in response to stress

the fight-or-flight response