: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Stress puts your body on alert, and, in turn, your body releases adrenaline, the fight-or-flight hormone. Alysse Dalessandro, Health, 18 Dec. 2024 Fear aggression emerges when a dog's fight-or-flight instinct activates. Daniel R. Depetris, Newsweek, 5 Dec. 2024 This reaction, triggered by your sympathetic nervous system, is called the fight-or-flight response. Anna Giorgi, Verywell Health, 29 Nov. 2024 Anxiety And Stress Are Altered Physiological States Stress and anxiety are a sign of the sympathetic nervous system escalating into the fight-or-flight response. Eric Wood, Forbes, 29 Nov. 2024 See all Example Sentences for fight-or-flight 

Word History

First Known Use

1973, in the meaning defined above

Time Traveler
The first known use of fight-or-flight was in 1973

Dictionary Entries Near fight-or-flight

Cite this Entry

“Fight-or-flight.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fight-or-flight. Accessed 25 Dec. 2024.

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
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!